/*  Prototype JavaScript framework, version 1.6.0.2
 *  (c) 2005-2008 Sam Stephenson
 *
 *  Prototype is freely distributable under the terms of an MIT-style license.
 *  For details, see the Prototype web site: http://www.prototypejs.org/
 *
 *--------------------------------------------------------------------------*/

/**
* @classDescription Declares the version of the prototype library.
*/

var Prototype = {
  Version: '1.6.0.2',

  Browser: {
    IE:     !!(window.attachEvent && !window.opera),
    Opera:  !!window.opera,
    WebKit: navigator.userAgent.indexOf('AppleWebKit/') > -1,
    Gecko:  navigator.userAgent.indexOf('Gecko') > -1 && navigator.userAgent.indexOf('KHTML') == -1,
    MobileSafari: !!navigator.userAgent.match(/Apple.*Mobile.*Safari/)
  },

  BrowserFeatures: {
    XPath: !!document.evaluate,
    ElementExtensions: !!window.HTMLElement,
    SpecificElementExtensions:
      document.createElement('div').__proto__ &&
      document.createElement('div').__proto__ !==
        document.createElement('form').__proto__
  },

  ScriptFragment: '<script[^>]*>([\\S\\s]*?)<\/script>',
  JSONFilter: /^\/\*-secure-([\s\S]*)\*\/\s*$/,

  emptyFunction: function() { },
  
   /**
    * Function to echo back the specified parameter.
     * @param {Object} x	Parameter to echo.
     * @return {Object} Returns the specified parameter.
     */
  K: function(x) { return x }
};

if (Prototype.Browser.MobileSafari)
  Prototype.BrowserFeatures.SpecificElementExtensions = false;


/* Based on Alex Arnell's inheritance implementation. */

/**
 * @classDescription Declares a class.
 * @constructor
 */
var Class = {
  create: function() {
    var parent = null, properties = $A(arguments);
    if (Object.isFunction(properties[0]))
      parent = properties.shift();

    function klass() {
      this.initialize.apply(this, arguments);
    }

    Object.extend(klass, Class.Methods);
    klass.superclass = parent;
    klass.subclasses = [];

    if (parent) {
      var subclass = function() { };
      subclass.prototype = parent.prototype;
      klass.prototype = new subclass;
      parent.subclasses.push(klass);
    }

    for (var i = 0; i < properties.length; i++)
      klass.addMethods(properties[i]);

    if (!klass.prototype.initialize)
      klass.prototype.initialize = Prototype.emptyFunction;

    klass.prototype.constructor = klass;

    return klass;
  }
};

Class.Methods = {
  addMethods: function(source) {
    var ancestor   = this.superclass && this.superclass.prototype;
    var properties = Object.keys(source);

    if (!Object.keys({ toString: true }).length)
      properties.push("toString", "valueOf");

    for (var i = 0, length = properties.length; i < length; i++) {
      var property = properties[i], value = source[property];
      if (ancestor && Object.isFunction(value) &&
          value.argumentNames().first() == "$super") {
        var method = value, value = Object.extend((function(m) {
          return function() { return ancestor[m].apply(this, arguments) };
        })(property).wrap(method), {
          valueOf:  function() { return method },
          toString: function() { return method.toString() }
        });
      }
      this.prototype[property] = value;
    }

    return this;
  }
};

var Abstract = { };

/**
 * Implements inheritance by copying the properties and methods from one element to another.
 * @alias Object.extend
 * @param {Object} destination	Destination object to inherit the properties and methods.
 * @param {Object} source	Source object to inherit properties and methods from.
 * @return {Object} Returns the destination object with the properties and methods from the source object.
 * @extends {Object}
 */
Object.extend = function(destination, source) {
  for (var property in source)
    destination[property] = source[property];
  return destination;
};

Object.extend(Object, {
  inspect: function(object) {
    try {
      if (Object.isUndefined(object)) return 'undefined';
      if (object === null) return 'null';
      return object.inspect ? object.inspect() : String(object);
    } catch (e) {
      if (e instanceof RangeError) return '...';
      throw e;
    }
  },

  toJSON: function(object) {
    var type = typeof object;
    switch (type) {
      case 'undefined':
      case 'function':
      case 'unknown': return;
      case 'boolean': return object.toString();
    }

    if (object === null) return 'null';
    if (object.toJSON) return object.toJSON();
    if (Object.isElement(object)) return;

    var results = [];
    for (var property in object) {
      var value = Object.toJSON(object[property]);
      if (!Object.isUndefined(value))
        results.push(property.toJSON() + ': ' + value);
    }

    return '{' + results.join(', ') + '}';
  },

  toQueryString: function(object) {
    return $H(object).toQueryString();
  },

  toHTML: function(object) {
    return object && object.toHTML ? object.toHTML() : String.interpret(object);
  },

  keys: function(object) {
    var keys = [];
    for (var property in object)
      keys.push(property);
    return keys;
  },

  values: function(object) {
    var values = [];
    for (var property in object)
      values.push(object[property]);
    return values;
  },

  clone: function(object) {
    return Object.extend({ }, object);
  },

  isElement: function(object) {
    return object && object.nodeType == 1;
  },

  isArray: function(object) {
    return object != null && typeof object == "object" &&
      'splice' in object && 'join' in object;
  },

  isHash: function(object) {
    return object instanceof Hash;
  },

  isFunction: function(object) {
    return typeof object == "function";
  },

  isString: function(object) {
    return typeof object == "string";
  },

  isNumber: function(object) {
    return typeof object == "number";
  },

  isUndefined: function(object) {
    return typeof object == "undefined";
  }
});

Object.extend(Function.prototype, {
  argumentNames: function() {
    var names = this.toString().match(/^[\s\(]*function[^(]*\((.*?)\)/)[1].split(",").invoke("strip");
    return names.length == 1 && !names[0] ? [] : names;
  },

  /**
   * Binds an instance of the function to the object that owns the function.
   * @alias Function.prototype.bind
   * @param {Function} function	Function to bind to its owner object.
   * @param {Object, Array} ... Arguments to use when calling the function.
   * @return {Object} Returns the function pre-bound to its owner object with the specified arguments.
   * @extends {Function}
   */
  bind: function() {
    if (arguments.length < 2 && Object.isUndefined(arguments[0])) return this;
    var __method = this, args = $A(arguments), object = args.shift();
    return function() {
      return __method.apply(object, args.concat($A(arguments)));
    }
  },

 /**
 * Binds an instance of a function to the object that owns the function as an event listener.
 * @alias Function.prototype.bindAsEventListener
 * @param {Object} object	Function to bind to its owner object.
 * @return {Object} Returns the function pre-bound to its owner object with the current event object as its argument.
 * @extends {Function}
 */
  bindAsEventListener: function() {
    var __method = this, args = $A(arguments), object = args.shift();
    return function(event) {
      return __method.apply(object, [event || window.event].concat(args));
    }
  },

  curry: function() {
    if (!arguments.length) return this;
    var __method = this, args = $A(arguments);
    return function() {
      return __method.apply(this, args.concat($A(arguments)));
    }
  },

  delay: function() {
    var __method = this, args = $A(arguments), timeout = args.shift() * 1000;
    return window.setTimeout(function() {
      return __method.apply(__method, args);
    }, timeout);
  },

  wrap: function(wrapper) {
    var __method = this;
    return function() {
      return wrapper.apply(this, [__method.bind(this)].concat($A(arguments)));
    }
  },

  methodize: function() {
    if (this._methodized) return this._methodized;
    var __method = this;
    return this._methodized = function() {
      return __method.apply(null, [this].concat($A(arguments)));
    };
  }
});

Function.prototype.defer = Function.prototype.delay.curry(0.01);

Date.prototype.toJSON = function() {
  return '"' + this.getUTCFullYear() + '-' +
    (this.getUTCMonth() + 1).toPaddedString(2) + '-' +
    this.getUTCDate().toPaddedString(2) + 'T' +
    this.getUTCHours().toPaddedString(2) + ':' +
    this.getUTCMinutes().toPaddedString(2) + ':' +
    this.getUTCSeconds().toPaddedString(2) + 'Z"';
};

/**
 * Tries the specified function calls until one of them is successful.
 * @alias Try.these
 * @param {Function, Array}	Function call(s) to try.
 * @return {String, Number}	Returns the value of the first successful function call.
 */
var Try = {
  these: function() {
    var returnValue;

    for (var i = 0, length = arguments.length; i < length; i++) {
      var lambda = arguments[i];
      try {
        returnValue = lambda();
        break;
      } catch (e) { }
    }

    return returnValue;
  }
};

RegExp.prototype.match = RegExp.prototype.test;

RegExp.escape = function(str) {
  return String(str).replace(/([.*+?^=!:${}()|[\]\/\\])/g, '\\$1');
};

/*--------------------------------------------------------------------------*/

/**
 * @classDescription Creates a PeriodicalExecuter object to call a function repeatedly at the specified interval.
 */
var PeriodicalExecuter = Class.create({
  
 /**
  * Initializes the PeriodicalExecutor object.
  * @alias PeriodicalExecutor.initialize
  * @param {Function} callback	Function to be called.
  * @param {Object} frequency	Interval (in seconds) to call the function at.
  */
  initialize: function(callback, frequency) {
    this.callback = callback;
    this.frequency = frequency;
    this.currentlyExecuting = false;

    this.registerCallback();
  },

/**
 * Registers a callback function.
 * @alias PeriodicalExecutor.registerCallback
 */
  registerCallback: function() {
    this.timer = setInterval(this.onTimerEvent.bind(this), this.frequency * 1000);
  },

  execute: function() {
    this.callback(this);
  },

/**
 * Stops execution of the timer event.
 * @alias PeriodicalExecutor.stop
 */
  stop: function() {
    if (!this.timer) return;
    clearInterval(this.timer);
    this.timer = null;
  },

/**
 * Calls the function at on the timer event.
 * @alias PeriodicalExecutor.onTimerEvent
 */
  onTimerEvent: function() {
    if (!this.currentlyExecuting) {
      try {
        this.currentlyExecuting = true;
        this.execute();
      } finally {
        this.currentlyExecuting = false;
      }
    }
  }
});
Object.extend(String, {
  interpret: function(value) {
    return value == null ? '' : String(value);
  },
  specialChar: {
    '\b': '\\b',
    '\t': '\\t',
    '\n': '\\n',
    '\f': '\\f',
    '\r': '\\r',
    '\\': '\\\\'
  }
});

Object.extend(String.prototype, {
  
  /**
   * Returns the string with every occurence of a given pattern replaced by either a regular string, the returned value of a function or a Template string. The pattern can be a string or a regular expression.
   * @alias String.gsub
   * @param {String} pattern	Pattern to replace.
   * @param {String} replacement	String to replace the pattern with.
   * @return {String}	Returns the string with every occurence of a given pattern replaced.
   * @extends {String}
   */
  gsub: function(pattern, replacement) {
    var result = '', source = this, match;
    replacement = arguments.callee.prepareReplacement(replacement);

    while (source.length > 0) {
      if (match = source.match(pattern)) {
        result += source.slice(0, match.index);
        result += String.interpret(replacement(match));
        source  = source.slice(match.index + match[0].length);
      } else {
        result += source, source = '';
      }
    }
    return result;
  },

  /**
   * Returns a string with the first count occurrences of pattern replaced by either a regular string, the returned value of a function or a Template string. pattern can be a string or a regular expression.
   * @alias String.sub
   * @param {String} pattern	Pattern to search for.
   * @param {String} replacement	Replacement string.
   * @param {Number} count	Number of occurrences to replace.
   * @return {String} Returns a string with the first count occurrences of pattern replaced by either a regular string, the returned value of a function or a Template string.
   * @extends {String}
   */
  sub: function(pattern, replacement, count) {
    replacement = this.gsub.prepareReplacement(replacement);
    count = Object.isUndefined(count) ? 1 : count;

    return this.gsub(pattern, function(match) {
      if (--count < 0) return match[0];
      return replacement(match);
    });
  },

  /**
   * Allows iterating over every occurrence of the given pattern (which can be a string or a regular expression).
   * @alias String.scan
   * @param {String} pattern	Pattern to search for.
   * @param {Iterator} iterator	Iterator to use.
   * @return {String} Returns the original string.
   * @extends {String}
   */
  scan: function(pattern, iterator) {
    this.gsub(pattern, iterator);
    return String(this);
  },

  /**
   * Truncates a string to the given length and appends a suffix to it (indicating that it is only an excerpt).
   * @alias String.truncate
   * @param {Object} length Length to truncate the string.
   * @param {Object} truncation Text to append to the string.
   * @return {String} Returns the truncated string.
   * @extends {String}
   */
  truncate: function(length, truncation) {
    length = length || 30;
    truncation = Object.isUndefined(truncation) ? '...' : truncation;
    return this.length > length ?
      this.slice(0, length - truncation.length) + truncation : String(this);
  },

  /**
   * Strips all leading and trailing whitespace from a string.
   * @alias String.strip
   * @return {String} Returns the string with the whitespace stripped.
   * @extends {String}
   */
  strip: function() {
    return this.replace(/^\s+/, '').replace(/\s+$/, '');
  },

/**
 * Removes the HTML or XML tags from a string.
 * @alias String.stripTags
 * @return {String} Returns the string with any HTML or XML tags removed.
 * @extends {String}
 */
  stripTags: function() {
    return this.replace(/<\/?[^>]+>/gi, '');
  },

/**
 * Removes any <script></script> blocks from a string.
 * @alias String.stripScripts()
 * @return {String} Returns the string with any <script></script> blocks removed.
 * @extends {String}
 */
  stripScripts: function() {
    return this.replace(new RegExp(Prototype.ScriptFragment, 'img'), '');
  },

  /**
  * Extracts any <script></script> blocks from a string and returns them as an array.
  * @alias String.extractScripts
  * @return	{Array} Returns an array of any <script></script> that the string contains.
  * @extends {String}
  */
  extractScripts: function() {
    var matchAll = new RegExp(Prototype.ScriptFragment, 'img');
    var matchOne = new RegExp(Prototype.ScriptFragment, 'im');
    return (this.match(matchAll) || []).map(function(scriptTag) {
      return (scriptTag.match(matchOne) || ['', ''])[1];
    });
  },

  /**
 * Evaluates the <script></script> blocks found in a string.
 * @alias String.evalScripts
 * @return {String, Number, Object, Boolean, Array} Returns the result of the script.
 * @extends {String}
 */
  evalScripts: function() {
    return this.extractScripts().map(function(script) { return eval(script) });
  },

  /**
 * Escapes any HTML characters in a string.
 * @alias String.escapeHTML()
 * @return {String} Returns the string with the HTML characters escaped.
 * @extends {String}
 */
  escapeHTML: function() {
    var self = arguments.callee;
    self.text.data = this;
    return self.div.innerHTML;
  },

  /**
 * Converts any escaped HTML characters in a string to real HTML characters.
 * @alias String.unescapeHTML()
 * @return {String} Returns the string with HTML characters unescaped.
 * @extends {String}
 */
  unescapeHTML: function() {
    var div = new Element('div');
    div.innerHTML = this.stripTags();
    return div.childNodes[0] ? (div.childNodes.length > 1 ?
      $A(div.childNodes).inject('', function(memo, node) { return memo+node.nodeValue }) :
      div.childNodes[0].nodeValue) : '';
  },

  /**
 * Creates an associative array (similar to a hash) from a string using parameter names as an index.
 * @alias String.toQueryParams()
 * @return {Array} Returns an associative array from the string.
 * @extends {String}
 */
  toQueryParams: function(separator) {
    var match = this.strip().match(/([^?#]*)(#.*)?$/);
    if (!match) return { };

    return match[1].split(separator || '&').inject({ }, function(hash, pair) {
      if ((pair = pair.split('='))[0]) {
        var key = decodeURIComponent(pair.shift());
        var value = pair.length > 1 ? pair.join('=') : pair[0];
        if (value != undefined) value = decodeURIComponent(value);

        if (key in hash) {
          if (!Object.isArray(hash[key])) hash[key] = [hash[key]];
          hash[key].push(value);
        }
        else hash[key] = value;
      }
      return hash;
    });
  },

  /**
 * Creates an array from the characters of a string.
 * @alias String.toArray()
 * @return {Array} Returns an array of all of the characters in a string.
 * @extends {String}
 */
  toArray: function() {
    return this.split('');
  },

  /**
   * Used internally by ObjectRange. Converts the last character of the string to the following character in the Unicode alphabet.
   * @alias String.succ
   * @return {String}	Returns the converted string.
   * @extends {String}
   */
  succ: function() {
    return this.slice(0, this.length - 1) +
      String.fromCharCode(this.charCodeAt(this.length - 1) + 1);
  },

   /**
   * Concatenates the string count times.
   * @alias String.times
   * @param {Number} count	Number of times to concatenate the string.
   * @return {String} Returns the concatenated string.
   * @extends {String}
   */
  times: function(count) {
    return count < 1 ? '' : new Array(count + 1).join(this);
  },

  /**
 * Converts  a hyphen-delimited string to camel case. (e.g. thisIsCamelCase)
 * @alias String.camelize()
 * @return {String} Returns the string as camel case.
 * @extends {String}
 */
  camelize: function() {
    var parts = this.split('-'), len = parts.length;
    if (len == 1) return parts[0];

    var camelized = this.charAt(0) == '-'
      ? parts[0].charAt(0).toUpperCase() + parts[0].substring(1)
      : parts[0];

    for (var i = 1; i < len; i++)
      camelized += parts[i].charAt(0).toUpperCase() + parts[i].substring(1);

    return camelized;
  },

  /**
   * Capitalizes the first letter of a string and downcases all the others.
   * @alias	String.capitalize
   * @return {String} Returns the capitalized string.
   * @extends {String}
   */
  capitalize: function() {
    return this.charAt(0).toUpperCase() + this.substring(1).toLowerCase();
  },

  /**
   * Converts a camelized string into a series of words separated by an underscore ("_").
   * @alias String.underscore
   * @return {String} Converts a camelized string into a series of words separated by an underscore ("_").
   * @extends {String}
   */
  underscore: function() {
    return this.gsub(/::/, '/').gsub(/([A-Z]+)([A-Z][a-z])/,'#{1}_#{2}').gsub(/([a-z\d])([A-Z])/,'#{1}_#{2}').gsub(/-/,'_').toLowerCase();
  },

  /**
   * Replaces every instance of the underscore character ("_") by a dash ("-").
   * @alias String.dasherize
   * @return {String}	Replaces every instance of the underscore character ("_") by a dash ("-").
   * @extends {String}
   */
  dasherize: function() {
    return this.gsub(/_/,'-');
  },

  /**
  * Converts the string to human-readable characters.
  * @alias String.inspect()
  * @return {String} Returns a version of the string that can easily be read by humans.
  * @extends {String}
  */
  inspect: function(useDoubleQuotes) {
    var escapedString = this.gsub(/[\x00-\x1f\\]/, function(match) {
      var character = String.specialChar[match[0]];
      return character ? character : '\\u00' + match[0].charCodeAt().toPaddedString(2, 16);
    });
    if (useDoubleQuotes) return '"' + escapedString.replace(/"/g, '\\"') + '"';
    return "'" + escapedString.replace(/'/g, '\\\'') + "'";
  },

  /**
   * Returns a JSON string.
   * @alias String.toJSON
   * @return {String}	Returns a JSON string.
   * @extends {String}
   */
  toJSON: function() {
    return this.inspect(true);
  },

  /**
   * Strips comment delimiters around Ajax JSON or JavaScript responses. This security method is called internally.
   * @alias String.unfilterJSON
   * @param {String} filter	Filter to use.
   * @return {String} Returns the unfiltered string.
   * @extends {String}
   */
  unfilterJSON: function(filter) {
    return this.sub(filter || Prototype.JSONFilter, '#{1}');
  },

  /**
   * Check if the string is valid JSON by the use of regular expressions. This security method is called internally.
   * @alias String.isJSON
   * @return {Boolean} Returns true if the string is a JSON string.
   * @extends {String}
   */
  isJSON: function() {
    var str = this;
    if (str.blank()) return false;
    str = this.replace(/\\./g, '@').replace(/"[^"\\\n\r]*"/g, '');
    return (/^[,:{}\[\]0-9.\-+Eaeflnr-u \n\r\t]*$/).test(str);
  },

  /**
   * Evaluates the JSON in the string and returns the resulting object. If the optional sanitize parameter is set to true, the string is checked for possible malicious attempts and eval is not called if one is detected.
   * @alias String.evalJSON
   * @param {Object} sanitize	If true, checks for malicious syntax.	
   * @return {Object}	Returns the result of the evaluation.
   * @extends {String}
   */
  evalJSON: function(sanitize) {
    var json = this.unfilterJSON();
    try {
      if (!sanitize || json.isJSON()) return eval('(' + json + ')');
    } catch (e) { }
    throw new SyntaxError('Badly formed JSON string: ' + this.inspect());
  },

  /**
   * Check if the string contains a pattern.
   * @alias String.include
   * @param {String} pattern	Pattern to search for.
   * @return {Boolean}	Returns true if the string contains a pattern.
   * @extends {String}
   */
  include: function(pattern) {
    return this.indexOf(pattern) > -1;
  },

  /**
   * Checks if the string starts with pattern.
   * @alias String.startsWith
   * @param {String} pattern	Pattern to search for.
   * @return {Boolean}	Returns true if the string starts with a pattern.
   * @extends {String}
   */
  startsWith: function(pattern) {
    return this.indexOf(pattern) === 0;
  },

  /**
   * Checks if the string ends with pattern.
   * @alias String.startsWith
   * @param {String} pattern	Pattern to search for.
   * @return {Boolean}	Returns true if the string starts with a pattern.
   * @extends {String}
   */
  endsWith: function(pattern) {
    var d = this.length - pattern.length;
    return d >= 0 && this.lastIndexOf(pattern) === d;
  },

  /**
   * Checks if the string is empty.
   * @alias String.empty
   * @return {Boolean} Returns true if the string is empty.
   * @extends {String}
   */
  empty: function() {
    return this == '';
  },

 /**
   * Check if the string is 'blank', meaning either empty or containing only whitespace.
   * @alias String.blank
   * @return {Boolean} Returns true if the string is blank.
   * @extends {String}
   */
  blank: function() {
    return /^\s*$/.test(this);
  },

  interpolate: function(object, pattern) {
    return new Template(this, pattern).evaluate(object);
  }
});

if (Prototype.Browser.WebKit || Prototype.Browser.IE) Object.extend(String.prototype, {
  escapeHTML: function() {
    return this.replace(/&/g,'&amp;').replace(/</g,'&lt;').replace(/>/g,'&gt;');
  },
  unescapeHTML: function() {
    return this.replace(/&amp;/g,'&').replace(/&lt;/g,'<').replace(/&gt;/g,'>');
  }
});

String.prototype.gsub.prepareReplacement = function(replacement) {
  if (Object.isFunction(replacement)) return replacement;
  var template = new Template(replacement);
  return function(match) { return template.evaluate(match) };
};

String.prototype.parseQuery = String.prototype.toQueryParams;

Object.extend(String.prototype.escapeHTML, {
  div:  document.createElement('div'),
  text: document.createTextNode('')
});

with (String.prototype.escapeHTML) div.appendChild(text);

/**
 * @classDescription Any time you have a group of similar objects and you need to produce formatted output for these objects, maybe inside a loop, you typically resort to concatenating string literals with the object's fields. There's nothing wrong with the above approach, except that it is hard to visualize the output immediately just by glancing at the concatenation expression. The Template class provides a much nicer and clearer way of achieving this formatting.
 */

var Template = Class.create({
  initialize: function(template, pattern) {
    this.template = template.toString();
    this.pattern = pattern || Template.Pattern;
  },

  /**
   * Applies the template to the given object's data, producing a formatted string with symbols replaced by corresponding object's properties.
   * @alias Template.evaluate
   * @param {Object} object	Object containing data.
   * @return {Object} Returns the formatted data.
   * @extends {Template}
   */
  evaluate: function(object) {
    if (Object.isFunction(object.toTemplateReplacements))
      object = object.toTemplateReplacements();

    return this.template.gsub(this.pattern, function(match) {
      if (object == null) return '';

      var before = match[1] || '';
      if (before == '\\') return match[2];

      var ctx = object, expr = match[3];
      var pattern = /^([^.[]+|\[((?:.*?[^\\])?)\])(\.|\[|$)/;
      match = pattern.exec(expr);
      if (match == null) return before;

      while (match != null) {
        var comp = match[1].startsWith('[') ? match[2].gsub('\\\\]', ']') : match[1];
        ctx = ctx[comp];
        if (null == ctx || '' == match[3]) break;
        expr = expr.substring('[' == match[3] ? match[1].length : match[0].length);
        match = pattern.exec(expr);
      }

      return before + String.interpret(ctx);
    });
  }
});
Template.Pattern = /(^|.|\r|\n)(#\{(.*?)\})/;

var $break = { };

/**
 * @classDescription Allows you to easily iterate items in a list.
 */

var Enumerable = {
  
  /**
 * Calls the specified iterator function.
 * @alias Enumerable.each
 * @param {Function} iterator	Iterator function to call. Takes the arguments elementValue, and elementIndex, respectively.
 */
  each: function(iterator, context) {
    var index = 0;
    iterator = iterator.bind(context);
    try {
      this._each(function(value) {
        iterator(value, index++);
      });
    } catch (e) {
      if (e != $break) throw e;
    }
    return this;
  },

  /**
   * Groups items in chunks based on a given size, with last chunk being possibly smaller.
   * @alias Enumerable.eachSlice
   * @param {Number} number	Number in each slice
   * @param {Object} iterator	Iterator to use
   * @return {Object} Returns formatted items.
   */
  eachSlice: function(number, iterator, context) {
    iterator = iterator ? iterator.bind(context) : Prototype.K;
    var index = -number, slices = [], array = this.toArray();
    while ((index += number) < array.length)
      slices.push(array.slice(index, index+number));
    return slices.collect(iterator, context);
  },

   /**
 * Calls an iterator function to test the values in a list to see if they are all true.
 * @alias Enumerable.all
 * @param {Function} iterator	Iterator function to call. Takes the arguments elementValue, and elementIndex, respectively.
 * @return {Boolean} Returns true if the iterator returns true for all elements.
 */
  all: function(iterator, context) {
    iterator = iterator ? iterator.bind(context) : Prototype.K;
    var result = true;
    this.each(function(value, index) {
      result = result && !!iterator(value, index);
      if (!result) throw $break;
    });
    return result;
  },

  /**
 * Calls an iterator function to test the values in a list to see if any are true.
 * @alias Enumerable.any
 * @param {Function} iterator	Iterator function to call. Takes the arguments elementValue, and elementIndex, respectively.
 * @return {Boolean} Returns true if any of the iterator returns true for any of the elements.
 */
  any: function(iterator, context) {
    iterator = iterator ? iterator.bind(context) : Prototype.K;
    var result = false;
    this.each(function(value, index) {
      if (result = !!iterator(value, index))
        throw $break;
    });
    return result;
  },

  /**
 * Calls an iterator function and returns the results in an Array.
 * @alias Enumerable.collect
 * @param {Function} iterator	Iterator function to call. Takes the arguments elementValue, and elementIndex, respectively.
 * @return {Array} Array of the results of calling the iterator on each element.
 */
  collect: function(iterator, context) {
    iterator = iterator ? iterator.bind(context) : Prototype.K;
    var results = [];
    this.each(function(value, index) {
      results.push(iterator(value, index));
    });
    return results;
  },

  /**
 * Calls an iterator function on the elements in a list and returns the first element that causes the iterator to return true.
 * @alias Enumerable.detect
 * @param {Function} iterator	Iterator function to call. Takes the arguments elementValue, and elementIndex, respectively.
 * @return {Object} Returns the first element that causes the iterator function to return true.
 */
  detect: function(iterator, context) {
    iterator = iterator.bind(context);
    var result;
    this.each(function(value, index) {
      if (iterator(value, index)) {
        result = value;
        throw $break;
      }
    });
    return result;
  },

  /**
 * Calls an iterator function on the elements in a list and returns all of the elements that cause the iterator to return true.
 * @alias Enumerable.findAll
 * @param {Function} iterator	Iterator function to call. Takes the arguments elementValue, and elementIndex, respectively.
 * @return {Array} Returns the elements that the cause the iterator to return true.
 */
  findAll: function(iterator, context) {
    iterator = iterator.bind(context);
    var results = [];
    this.each(function(value, index) {
      if (iterator(value, index))
        results.push(value);
    });
    return results;
  },

  /**
 * Tests each element in a list to see if it contains the specified regular expression.
 * @alias Enumerable.grep
 * @param {RegExp} pattern	RegExp to match.
 * @param {Function} [iterator]	Iterator function to call. Takes the arguments elementValue, and elementIndex, respectively.
 * @return {Array} Returns an array of the elements with a match to the RegExp. If you specify an iterator, returns the result of calling the iterator on the match.
 */
  grep: function(filter, iterator, context) {
    iterator = iterator ? iterator.bind(context) : Prototype.K;
    var results = [];

    if (Object.isString(filter))
      filter = new RegExp(filter);

    this.each(function(value, index) {
      if (filter.match(value))
        results.push(iterator(value, index));
    });
    return results;
  },

  /**
 * Searches the list of elements for the specified object.
 * @alias Enumerable.include
 * @param {Object} object	Object to search for.
 * @return {Boolean} Returns true if the list of elements contains the object.
 */
  include: function(object) {
    if (Object.isFunction(this.indexOf))
      if (this.indexOf(object) != -1) return true;

    var found = false;
    this.each(function(value) {
      if (value == object) {
        found = true;
        throw $break;
      }
    });
    return found;
  },

  /**
   * Groups items in fixed-size chunks, using a specific value to fill up the last chunk if necessary.
   * @alias Enumerable.inGroupsOf
   * @param {Number} number	Number in each group
   * @param {Object} fillWith	Value to fill with
   * @return {Object} Returns formatted data.
   */
  inGroupsOf: function(number, fillWith) {
    fillWith = Object.isUndefined(fillWith) ? null : fillWith;
    return this.eachSlice(number, function(slice) {
      while(slice.length < number) slice.push(fillWith);
      return slice;
    });
  },

  /**
 * Calls an iterator function on the elements in a list and accumulates their values into a single value.
 * @alias Enumerable.inject
 * @param {Object} memo	Initial value for the iterator.
 * @param {Function} iterator	Iterator function to call. Takes the arguments elementValue, and elementIndex, respectively.
 * @return {Object} Returns the final accumulated result.
 */
  inject: function(memo, iterator, context) {
    iterator = iterator.bind(context);
    this.each(function(value, index) {
      memo = iterator(memo, value, index);
    });
    return memo;
  },

  /**
 * Calls the specified method on each element in a list and returns an array of the results.
 * @alias Enumerable.invoke
 * @param {Function} method	Method to call.
 * @return {Array} Returns an array of the results.
 */
  invoke: function(method) {
    var args = $A(arguments).slice(1);
    return this.map(function(value) {
      return value[method].apply(value, args);
    });
  },

  /**
 * Returns the element in the list with the greatest value. If you specify an iterator, calls the iterator function and returns the result with the greatest value.
 * @alias Enumerable.max
 * @param {Function} [iterator]	Iterator function to call. Takes the arguments elementValue, and elementIndex, respectively.
 * @return {Object} Returns the element in the list with the greatest value. If you specify an iterator, calls the iterator function and returns the result with the greatest value.
 */
  max: function(iterator, context) {
    iterator = iterator ? iterator.bind(context) : Prototype.K;
    var result;
    this.each(function(value, index) {
      value = iterator(value, index);
      if (result == null || value >= result)
        result = value;
    });
    return result;
  },

  /**
 * Returns the element in the list with the smallest value. If you specify an iterator, calls the iterator function and returns the result with the smallest value.
 * @alias Enumerable.min
 * @param {Function} [iterator]	Iterator function to call. Takes the arguments elementValue, and elementIndex, respectively.
 * @return {Object} Returns the element in the list with the smallest value. If you specify an iterator, calls the iterator function and returns the result with the smallest value.
 */
  min: function(iterator, context) {
    iterator = iterator ? iterator.bind(context) : Prototype.K;
    var result;
    this.each(function(value, index) {
      value = iterator(value, index);
      if (result == null || value < result)
        result = value;
    });
    return result;
  },

  /**
 * Partitions a list of elements into true elements or values and not-true elements or values.
 * @alias Enumerable.partition
 * @param {Object} [iterator]	Iterator function to call. Takes the arguments elementValue, and elementIndex, respectively.
 * @return {Array} Returns an array of two elements--both of which are arrays. The first array contains all true elements or values (if you specify an iterator) and the second array contains not-true elements or values.
 */
  partition: function(iterator, context) {
    iterator = iterator ? iterator.bind(context) : Prototype.K;
    var trues = [], falses = [];
    this.each(function(value, index) {
      (iterator(value, index) ?
        trues : falses).push(value);
    });
    return [trues, falses];
  },

  /**
 * Retrieves the value for the specified property for each element in an array.
 * @alias Enumerable.pluck
 * @param {String} property	Name of the property to get.
 * @return {Array} Returns an array of the property values.
 */
  pluck: function(property) {
    var results = [];
    this.each(function(value) {
      results.push(value[property]);
    });
    return results;
  },

  /**
 * Calls an iterator function on the elements in a list and returns all of the elements that cause the iterator to return false.
 * @alias Enumerable.reject
 * @param {Function} iterator	Iterator function to call. Takes the arguments elementValue, and elementIndex, respectively.
 * @return {Array} Returns the elements that the cause the iterator to return false.
 */
  reject: function(iterator, context) {
    iterator = iterator.bind(context);
    var results = [];
    this.each(function(value, index) {
      if (!iterator(value, index))
        results.push(value);
    });
    return results;
  },

  /**
 * Sorts the elements in a list by their iterator results.
 * @alias Enumerable.sortBy
 * @param {Object} iterator	Iterator function to call. Takes the arguments elementValue, and elementIndex, respectively.
 * @return {Array} Returns an array of elements sorted by their iterator results.
 */
  sortBy: function(iterator, context) {
    iterator = iterator.bind(context);
    return this.map(function(value, index) {
      return {value: value, criteria: iterator(value, index)};
    }).sort(function(left, right) {
      var a = left.criteria, b = right.criteria;
      return a < b ? -1 : a > b ? 1 : 0;
    }).pluck('value');
  },

  /**
 * Creates an array of the elements in a list.
 * @alias Enumerable.toArray
 * @return {Array} Returns an Array of elements in the list.
 */
  toArray: function() {
    return this.map();
  },

  /**
 * Merges elements from one or more lists into a single list.
 * @alias Enumerable.zip()
 * @param {Array} ... One or more lists of elements to merge.
 * @return {Array} Returns a single array.
 */
  zip: function() {
    var iterator = Prototype.K, args = $A(arguments);
    if (Object.isFunction(args.last()))
      iterator = args.pop();

    var collections = [this].concat(args).map($A);
    return this.map(function(value, index) {
      return iterator(collections.pluck(index));
    });
  },

  /**
   * Returns the size of the enumeration.
   * @alias Enumerable.size
   * @return {Number} Returns the size of the enumeration.
   */
  size: function() {
    return this.toArray().length;
  },

  /**
 * Returns a human-readable string version of the list of elements.
 * @alias Enumerable.inspect
 * @return {String} Returns a human-readable string version of the list of elements.
 */
  inspect: function() {
    return '#<Enumerable:' + this.toArray().inspect() + '>';
  }
};

Object.extend(Enumerable, {
  map:     Enumerable.collect,
  find:    Enumerable.detect,
  select:  Enumerable.findAll,
  filter:  Enumerable.findAll,
  member:  Enumerable.include,
  entries: Enumerable.toArray,
  every:   Enumerable.all,
  some:    Enumerable.any
});

/**
 * Converts the argument "iterable" into an Array object.
 * @alias $A
 * @param {Object} iterable	Object to be converted to an Array.
 * @return {Array} Returns an Array.
 */
function $A(iterable) {
  if (!iterable) return [];
  if (iterable.toArray) return iterable.toArray();
  var length = iterable.length || 0, results = new Array(length);
  while (length--) results[length] = iterable[length];
  return results;
}

if (Prototype.Browser.WebKit) {
  $A = function(iterable) {
    if (!iterable) return [];
    if (!(Object.isFunction(iterable) && iterable == '[object NodeList]') &&
        iterable.toArray) return iterable.toArray();
    var length = iterable.length || 0, results = new Array(length);
    while (length--) results[length] = iterable[length];
    return results;
  };
}

Array.from = $A;

Object.extend(Array.prototype, Enumerable);

if (!Array.prototype._reverse) Array.prototype._reverse = Array.prototype.reverse;

Object.extend(Array.prototype, {
  _each: function(iterator) {
    for (var i = 0, length = this.length; i < length; i++)
      iterator(this[i]);
  },

  /**
 * Clears an array of all content.
 * @alias Array.clear
 * @return {Array} Returns an empty array.
 * @extends {Array}
 */
  clear: function() {
    this.length = 0;
    return this;
  },

  /**
 * Returns the first element of an array.
 * @alias Array.first
 * @return {Object, String, Number} Returns the first element of an array.
 * @extends {Array}
 */
  first: function() {
    return this[0];
  },

  /**
 * Returns the last element of an array.
 * @alias Array.last
 * @return {Object, String, Number} Returns the last element of an array.
 * @extends {Array}
 */
  last: function() {
    return this[this.length - 1];
  },

  /**
   * Returns a new version of the array, without any null/undefined values.
   * @alias Array.compact
   * @return {Array}	Returns a new version of the array, without any null/undefined values.
   * @extends {Array}
   */
  compact: function() {
    return this.select(function(value) {
      return value != null;
    });
  },

  /**
 * Flattens an array containing elements that are arrays into a single array.
 * @alias Array.flatten
 * @return {Array} Returns a one-dimensional array.
 * @extends {Array}
 */
  flatten: function() {
    return this.inject([], function(array, value) {
      return array.concat(Object.isArray(value) ?
        value.flatten() : [value]);
    });
  },

  /**
  * Returns an array without the specified elements.
  * @alias Array.without
  * @param {Array, String, Number} ... One or more elements to exclude from the array.
  * @return {Array} Returns an array without the specified elements.
  * @extends {Array}
  */
  without: function() {
    var values = $A(arguments);
    return this.select(function(value) {
      return !values.include(value);
    });
  },

  /**
  * Reverses the order of elements in an array.
  * @alias Array.reverse
  * @param {Boolean} inline	If true, indicates that the array itself should be reversed, instead of just creating a copy. Default is true.
  * @return {Array} Returns an array with the order of its elements reversed.
  * @extends {Array}
  */
  reverse: function(inline) {
    return (inline !== false ? this : this.toArray())._reverse();
  },

  /**
   * Reduces arrays: one-element arrays are turned into their unique element, while multiple-element arrays are returned untouched.
   * @alias Array.reduce
   * @return {Array} Returns the reduced array.
   * @extends {Array}
   */
  reduce: function() {
    return this.length > 1 ? this : this[0];
  },

  /**
   * Produces a duplicate-free version of an array. If no duplicates are found, the original array is returned.
   * @alias Array.uniq
   * @param {Object} sorted
   * @return {Array} Produces a duplicate-free version of an array. If no duplicates are found, the original array is returned.
   * @extends {Array}
   */
  uniq: function(sorted) {
    return this.inject([], function(array, value, index) {
      if (0 == index || (sorted ? array.last() != value : !array.include(value)))
        array.push(value);
      return array;
    });
  },

  intersect: function(array) {
    return this.uniq().findAll(function(item) {
      return array.detect(function(value) { return item === value });
    });
  },

  /**
   * Returns a duplicate of the array, leaving the original array intact.
   * @alias Array.clone
   * @return {Array} Returns a duplicate of the array, leaving the original array intact.
   * @extends {Array}
   */
  clone: function() {
    return [].concat(this);
  },

  /**
   * Returns the size of the array.
   * @alias Array.size
   * @return {Array} Returns the size of the array.
   * @extends {Array}
   */
  size: function() {
    return this.length;
  },

  /**
  * Formats an array into a human-readable string.
  * @alias Array.inspect
  * @return {String} Returns a string version of the array.
  * @extends {Array}
  */
  inspect: function() {
    return '[' + this.map(Object.inspect).join(', ') + ']';
  },

  /**
   * Returns a JSON string.
   * @alias Array.toJSON
   * @return {Array}	Returns a JSON string.
   * @extends {Array}
   */
  toJSON: function() {
    var results = [];
    this.each(function(object) {
      var value = Object.toJSON(object);
      if (!Object.isUndefined(value)) results.push(value);
    });
    return '[' + results.join(', ') + ']';
  }
});

// use native browser JS 1.6 implementation if available
if (Object.isFunction(Array.prototype.forEach))
  Array.prototype._each = Array.prototype.forEach;

if (!Array.prototype.indexOf) Array.prototype.indexOf = function(item, i) {
  i || (i = 0);
  var length = this.length;
  if (i < 0) i = length + i;
  for (; i < length; i++)
    if (this[i] === item) return i;
  return -1;
};

if (!Array.prototype.lastIndexOf) Array.prototype.lastIndexOf = function(item, i) {
  i = isNaN(i) ? this.length : (i < 0 ? this.length + i : i) + 1;
  var n = this.slice(0, i).reverse().indexOf(item);
  return (n < 0) ? n : i - n - 1;
};

Array.prototype.toArray = Array.prototype.clone;

/**
 * Splits a string into an Array, treating all whitespace as delimiters. Equivalent to Ruby's %w{foo bar} or Perl's qw(foo bar).
 * @alias $w
 * @param {String} string	String to split into an array
 * @return {Array} Returns an array.
 */
function $w(string) {
  if (!Object.isString(string)) return [];
  string = string.strip();
  return string ? string.split(/\s+/) : [];
}

if (Prototype.Browser.Opera){
  Array.prototype.concat = function() {
    var array = [];
    for (var i = 0, length = this.length; i < length; i++) array.push(this[i]);
    for (var i = 0, length = arguments.length; i < length; i++) {
      if (Object.isArray(arguments[i])) {
        for (var j = 0, arrayLength = arguments[i].length; j < arrayLength; j++)
          array.push(arguments[i][j]);
      } else {
        array.push(arguments[i]);
      }
    }
    return array;
  };
}
Object.extend(Number.prototype, {
  toColorPart: function() {
    return this.toPaddedString(2, 16);
  },

  succ: function() {
    return this + 1;
  },

  times: function(iterator) {
    $R(0, this, true).each(iterator);
    return this;
  },

  toPaddedString: function(length, radix) {
    var string = this.toString(radix || 10);
    return '0'.times(length - string.length) + string;
  },

  toJSON: function() {
    return isFinite(this) ? this.toString() : 'null';
  }
});

$w('abs round ceil floor').each(function(method){
  Number.prototype[method] = Math[method].methodize();
});

/**
 * Converts the argument "object" into a hash.
 * @alias $H
 * @param {Object} object	Object to be converted to a hash.
 * @return {Object} Returns a hash object.
 */
function $H(object) {
  return new Hash(object);
};

/**
 * @classDescription Hash can be thought of as an associative array, binding unique keys to values (which are not necessarily unique), though it can not guarantee consistent order its elements when iterating. Because of the nature of JavaScript programming language, every object is in fact a hash; but Hash adds a number of methods that let you enumerate keys and values, iterate over key/value pairs, merge two hashes together, encode the hash into a query string representation, etc.
 */
var Hash = Class.create(Enumerable, (function() {

  function toQueryPair(key, value) {
    if (Object.isUndefined(value)) return key;
    return key + '=' + encodeURIComponent(String.interpret(value));
  }

  return {
    initialize: function(object) {
      this._object = Object.isHash(object) ? object.toObject() : Object.clone(object);
    },

    _each: function(iterator) {
      for (var key in this._object) {
        var value = this._object[key], pair = [key, value];
        pair.key = key;
        pair.value = value;
        iterator(pair);
      }
    },

    set: function(key, value) {
      return this._object[key] = value;
    },

    get: function(key) {
      return this._object[key];
    },

    unset: function(key) {
      var value = this._object[key];
      delete this._object[key];
      return value;
    },

    toObject: function() {
      return Object.clone(this._object);
    },

   /**
    * Creates an array of the keys in a hash.
  	* @alias Hash.keys
    * @return {Array} Returns an array of keys.
 	*/
	keys: function() {
      return this.pluck('key');
    },

  /**
  * Creates an array of the values in a hash.
  * @alias Hash.values
  * @return {Array} Returns an array of values.
  */
	values: function() {
      return this.pluck('value');
    },

    index: function(value) {
      var match = this.detect(function(pair) {
        return pair.value === value;
      });
      return match && match.key;
    },

  /**
  * Merges this hash with the specified hash.
  * @alias Hash.merge()
  * @param {Object} hash	Hash to merge with.
  * @return {Object} Returns the merged hash.
  */
	merge: function(object) {
      return this.clone().update(object);
    },

    update: function(object) {
      return new Hash(object).inject(this, function(result, pair) {
        result.set(pair.key, pair.value);
        return result;
      });
    },

      /**
  * Returns the keys and values of a hash formatted into a query string. (e.g. 'key1=value1&key2=value2')
  * @alias Hash.toQueryString
  * @return {String} Returns a query string version of the hash.
  */
	toQueryString: function() {
      return this.map(function(pair) {
        var key = encodeURIComponent(pair.key), values = pair.value;

        if (values && typeof values == 'object') {
          if (Object.isArray(values))
            return values.map(toQueryPair.curry(key)).join('&');
        }
        return toQueryPair(key, values);
      }).join('&');
    },

      /**
  * Formats the hash into a human-readable string of key:value pairs.
  * @alias Hash.inspect
  * @return {String} Returns a string version of the key:value pairs of the hash.
  */
	inspect: function() {
      return '#<Hash:{' + this.map(function(pair) {
        return pair.map(Object.inspect).join(': ');
      }).join(', ') + '}>';
    },

  /**
   * Returns a JSON string.
   * @alias Hash.toJSON
   * @return {String} Returns a JSON string.
   */
    toJSON: function() {
      return Object.toJSON(this.toObject());
    },

    clone: function() {
      return new Hash(this);
    }
  }
})());

Hash.prototype.toTemplateReplacements = Hash.prototype.toObject;
Hash.from = $H;
var ObjectRange = Class.create(Enumerable, {
  initialize: function(start, end, exclusive) {
    this.start = start;
    this.end = end;
    this.exclusive = exclusive;
  },

  _each: function(iterator) {
    var value = this.start;
    while (this.include(value)) {
      iterator(value);
      value = value.succ();
    }
  },

  /**
  * Checks if the specified value is included in the range.
  * @alias ObjectRange.include
  * @param {Object} value	Value to search for.
  * @return {Boolean} Returns true if the value is included in the range.
  */
  include: function(value) {
    if (value < this.start)
      return false;
    if (this.exclusive)
      return value < this.end;
    return value <= this.end;
  }
});

/**
 * Creates a new ObjectRange using the specified bounds.
 * @alias $R
 * @param {Object} start	Start point of the range.
 * @param {Object} end	End point of the range.
 * @param {Boolean} exclusive	If true, indicates that the start and end points should be excluded from the ObjectRange.
 * @constructor
 * @return {ObjectRange} Returns a new ObjectRange.
 */
var $R = function(start, end, exclusive) {
  return new ObjectRange(start, end, exclusive);
};

/**
 * @classDescription Prototype offers several objects to deal with AJAX communication. With Prototype, going Ajaxy is downright simple! All objects share a common set of options, which are discussed separately.
 */
var Ajax = {
  
   /**
 * Creates a new XMLHttpRequest object.
 * @alias Ajax.getTransport
 * @return {XMLHttpRequest} Returns a new XMLHttpRequest object.
 */
  getTransport: function() {
    return Try.these(
      function() {return new XMLHttpRequest()},
      function() {return new ActiveXObject('Msxml2.XMLHTTP')},
      function() {return new ActiveXObject('Microsoft.XMLHTTP')}
    ) || false;
  },

  activeRequestCount: 0
};

Ajax.Responders = {
    /**
  * Array of objects that are registered for AJAX event notifications.
  * @alias Ajax.responders
  */
  responders: [],

  _each: function(iterator) {
    this.responders._each(iterator);
  },

  /**
  * Calls the methods associated with the responderToAdd object when the corresponding event occurs.
  * @alias Ajax.Responders.register
  * @param {Object} responderToAdd	Object containing the methods to call. Should be named the same as the appropriate AJAX event.
  * @extends {Enumerable}
  */
  register: function(responder) {
    if (!this.include(responder))
      this.responders.push(responder);
  },

  /**
  * Removes the responderToRemove object from the list of registered objects.
  * @alias Ajax.Responders.unregister
  * @param {Object} responderToRemove
  * @extends {Enumerable}
  */
  unregister: function(responder) {
    this.responders = this.responders.without(responder);
  },

  /**
  * For each object in the list, calls the method specified in callback using request, transport, and json as arguments.
  * @alias Ajax.Responders.dispatch
  * @param {Object} callback	Name of the AJAX event.
  * @param {Object} request	Ajax.Request object responsible for the event.
  * @param {Object} transport	XMLHttpRequest object that carries the AJAX call.
  * @param {Object} json	X-JSON header of the response.
  * @extends {Enumerable}
  */
  dispatch: function(callback, request, transport, json) {
    this.each(function(responder) {
      if (Object.isFunction(responder[callback])) {
        try {
          responder[callback].apply(responder, [request, transport, json]);
        } catch (e) { }
      }
    });
  }
};

Object.extend(Ajax.Responders, Enumerable);

Ajax.Responders.register({
  onCreate:   function() { Ajax.activeRequestCount++ },
  onComplete: function() { Ajax.activeRequestCount-- }
});

/**
 * @classDescription Base class for most other classes defined by the Ajax object.
 * @constructor
 */
Ajax.Base = Class.create({
  initialize: function(options) {
    this.options = {
      method:       'post',
      asynchronous: true,
      contentType:  'application/x-www-form-urlencoded',
      encoding:     'UTF-8',
      parameters:   '',
      evalJSON:     true,
      evalJS:       true
    };
    Object.extend(this.options, options || { });

    this.options.method = this.options.method.toLowerCase();

    if (Object.isString(this.options.parameters))
      this.options.parameters = this.options.parameters.toQueryParams();
    else if (Object.isHash(this.options.parameters))
      this.options.parameters = this.options.parameters.toObject();
  }
});

/**
 * @classDescription Contains properties and methods to compose an AJAX request to send to the server.
 * @constructor
 * @alias Ajax.Request
 */
Ajax.Request = Class.create(Ajax.Base, {
  _complete: false,

  initialize: function($super, url, options) {
    $super(options);
    this.transport = Ajax.getTransport();
    this.request(url);
  },

  request: function(url) {
    this.url = url;
    this.method = this.options.method;
    var params = Object.clone(this.options.parameters);

    if (!['get', 'post'].include(this.method)) {
      // simulate other verbs over post
      params['_method'] = this.method;
      this.method = 'post';
    }

    this.parameters = params;

    if (params = Object.toQueryString(params)) {
      // when GET, append parameters to URL
      if (this.method == 'get')
        this.url += (this.url.include('?') ? '&' : '?') + params;
      else if (/Konqueror|Safari|KHTML/.test(navigator.userAgent))
        params += '&_=';
    }

    try {
      var response = new Ajax.Response(this);
      if (this.options.onCreate) this.options.onCreate(response);
      Ajax.Responders.dispatch('onCreate', this, response);

      this.transport.open(this.method.toUpperCase(), this.url,
        this.options.asynchronous);

      if (this.options.asynchronous) this.respondToReadyState.bind(this).defer(1);

      this.transport.onreadystatechange = this.onStateChange.bind(this);
      this.setRequestHeaders();

      this.body = this.method == 'post' ? (this.options.postBody || params) : null;
      this.transport.send(this.body);

      /* Force Firefox to handle ready state 4 for synchronous requests */
      if (!this.options.asynchronous && this.transport.overrideMimeType)
        this.onStateChange();

    }
    catch (e) {
      this.dispatchException(e);
    }
  },

  onStateChange: function() {
    var readyState = this.transport.readyState;
    if (readyState > 1 && !((readyState == 4) && this._complete))
      this.respondToReadyState(this.transport.readyState);
  },

  setRequestHeaders: function() {
    var headers = {
      'X-Requested-With': 'XMLHttpRequest',
      'X-Prototype-Version': Prototype.Version,
      'Accept': 'text/javascript, text/html, application/xml, text/xml, */*'
    };

    if (this.method == 'post') {
      headers['Content-type'] = this.options.contentType +
        (this.options.encoding ? '; charset=' + this.options.encoding : '');

      /* Force "Connection: close" for older Mozilla browsers to work
       * around a bug where XMLHttpRequest sends an incorrect
       * Content-length header. See Mozilla Bugzilla #246651.
       */
      if (this.transport.overrideMimeType &&
          (navigator.userAgent.match(/Gecko\/(\d{4})/) || [0,2005])[1] < 2005)
            headers['Connection'] = 'close';
    }

    // user-defined headers
    if (typeof this.options.requestHeaders == 'object') {
      var extras = this.options.requestHeaders;

      if (Object.isFunction(extras.push))
        for (var i = 0, length = extras.length; i < length; i += 2)
          headers[extras[i]] = extras[i+1];
      else
        $H(extras).each(function(pair) { headers[pair.key] = pair.value });
    }

    for (var name in headers)
      this.transport.setRequestHeader(name, headers[name]);
  },

  success: function() {
    var status = this.getStatus();
    return !status || (status >= 200 && status < 300);
  },

  getStatus: function() {
    try {
      return this.transport.status || 0;
    } catch (e) { return 0 }
  },

  respondToReadyState: function(readyState) {
    var state = Ajax.Request.Events[readyState], response = new Ajax.Response(this);

    if (state == 'Complete') {
      try {
        this._complete = true;
        (this.options['on' + response.status]
         || this.options['on' + (this.success() ? 'Success' : 'Failure')]
         || Prototype.emptyFunction)(response, response.headerJSON);
      } catch (e) {
        this.dispatchException(e);
      }

      var contentType = response.getHeader('Content-type');
      if (this.options.evalJS == 'force'
          || (this.options.evalJS && this.isSameOrigin() && contentType
          && contentType.match(/^\s*(text|application)\/(x-)?(java|ecma)script(;.*)?\s*$/i)))
        this.evalResponse();
    }

    try {
      (this.options['on' + state] || Prototype.emptyFunction)(response, response.headerJSON);
      Ajax.Responders.dispatch('on' + state, this, response, response.headerJSON);
    } catch (e) {
      this.dispatchException(e);
    }

    if (state == 'Complete') {
      // avoid memory leak in MSIE: clean up
      this.transport.onreadystatechange = Prototype.emptyFunction;
    }
  },

  isSameOrigin: function() {
    var m = this.url.match(/^\s*https?:\/\/[^\/]*/);
    return !m || (m[0] == '#{protocol}//#{domain}#{port}'.interpolate({
      protocol: location.protocol,
      domain: document.domain,
      port: location.port ? ':' + location.port : ''
    }));
  },

  getHeader: function(name) {
    try {
      return this.transport.getResponseHeader(name) || null;
    } catch (e) { return null }
  },

  evalResponse: function() {
    try {
      return eval((this.transport.responseText || '').unfilterJSON());
    } catch (e) {
      this.dispatchException(e);
    }
  },

  dispatchException: function(exception) {
    (this.options.onException || Prototype.emptyFunction)(this, exception);
    Ajax.Responders.dispatch('onException', this, exception);
  }
});

/**
 * List of possible events and statuses associated with an AJAX operation.
 * @extends {Ajax.Base}
 */
Ajax.Request.Events =
  ['Uninitialized', 'Loading', 'Loaded', 'Interactive', 'Complete'];

Ajax.Response = Class.create({
  
    /**
  * Inititializes a new Ajax request.
  * @alias Ajax.Request.initialize
  * @param {Object} url	URL target for the request.
  * @param {Object} options	Options to set.
  * @extends {Ajax.Base}
  */
  initialize: function(request){
    this.request = request;
    var transport  = this.transport  = request.transport,
        readyState = this.readyState = transport.readyState;

    if((readyState > 2 && !Prototype.Browser.IE) || readyState == 4) {
      this.status       = this.getStatus();
      this.statusText   = this.getStatusText();
      this.responseText = String.interpret(transport.responseText);
      this.headerJSON   = this._getHeaderJSON();
    }

    if(readyState == 4) {
      var xml = transport.responseXML;
      this.responseXML  = Object.isUndefined(xml) ? null : xml;
      this.responseJSON = this._getResponseJSON();
    }
  },

  status:      0,
  statusText: '',

  getStatus: Ajax.Request.prototype.getStatus,

  getStatusText: function() {
    try {
      return this.transport.statusText || '';
    } catch (e) { return '' }
  },

  getHeader: Ajax.Request.prototype.getHeader,

  getAllHeaders: function() {
    try {
      return this.getAllResponseHeaders();
    } catch (e) { return null }
  },

  getResponseHeader: function(name) {
    return this.transport.getResponseHeader(name);
  },

  getAllResponseHeaders: function() {
    return this.transport.getAllResponseHeaders();
  },

  _getHeaderJSON: function() {
    var json = this.getHeader('X-JSON');
    if (!json) return null;
    json = decodeURIComponent(escape(json));
    try {
      return json.evalJSON(this.request.options.sanitizeJSON ||
        !this.request.isSameOrigin());
    } catch (e) {
      this.request.dispatchException(e);
    }
  },

  _getResponseJSON: function() {
    var options = this.request.options;
    if (!options.evalJSON || (options.evalJSON != 'force' &&
      !(this.getHeader('Content-type') || '').include('application/json')) ||
        this.responseText.blank())
          return null;
    try {
      return this.responseText.evalJSON(options.sanitizeJSON ||
        !this.request.isSameOrigin());
    } catch (e) {
      this.request.dispatchException(e);
    }
  }
});

/**
 * @classDescription	Contains properties and methods to update an HTML element with content from the server.
 * @constructor
 * @alias Ajax.Updater
 */
Ajax.Updater = Class.create(Ajax.Request, {
  initialize: function($super, container, url, options) {
    this.container = {
      success: (container.success || container),
      failure: (container.failure || (container.success ? null : container))
    };

    options = Object.clone(options);
    var onComplete = options.onComplete;
    options.onComplete = (function(response, json) {
      this.updateContent(response.responseText);
      if (Object.isFunction(onComplete)) onComplete(response, json);
    }).bind(this);

    $super(url, options);
  },

  updateContent: function(responseText) {
    var receiver = this.container[this.success() ? 'success' : 'failure'],
        options = this.options;

    if (!options.evalScripts) responseText = responseText.stripScripts();

    if (receiver = $(receiver)) {
      if (options.insertion) {
        if (Object.isString(options.insertion)) {
          var insertion = { }; insertion[options.insertion] = responseText;
          receiver.insert(insertion);
        }
        else options.insertion(receiver, responseText);
      }
      else receiver.update(responseText);
    }
  }
});

/**
 * @classDescription Periodically performs an AJAX request and updates a container�s contents based on the response text. Offers a mechanism for �decay,� which lets it trigger at widening intervals while the response is unchanged.
 * @alias Ajax.PeriodicalUpdater
 */
Ajax.PeriodicalUpdater = Class.create(Ajax.Base, {
  initialize: function($super, container, url, options) {
    $super(options);
    this.onComplete = this.options.onComplete;

    this.frequency = (this.options.frequency || 2);
    this.decay = (this.options.decay || 1);

    this.updater = { };
    this.container = container;
    this.url = url;

    this.start();
  },

  start: function() {
    this.options.onComplete = this.updateComplete.bind(this);
    this.onTimerEvent();
  },

  stop: function() {
    this.updater.options.onComplete = undefined;
    clearTimeout(this.timer);
    (this.onComplete || Prototype.emptyFunction).apply(this, arguments);
  },

  updateComplete: function(response) {
    if (this.options.decay) {
      this.decay = (response.responseText == this.lastText ?
        this.decay * this.options.decay : 1);

      this.lastText = response.responseText;
    }
    this.timer = this.onTimerEvent.bind(this).delay(this.decay * this.frequency);
  },

  onTimerEvent: function() {
    this.updater = new Ajax.Updater(this.container, this.url, this.options);
  }
});

/**
 * If provided with a string, returns the element in the document with matching ID; otherwise returns the passed element. Takes in an arbitrary number of arguments. All elements returned by the function are extended with Prototype DOM extensions.
 * @alias $
 * @param {String} element	ID of the element to return
 * @return {HTMLElement} Returns the matching element.
 */
function $(element) {
  if (arguments.length > 1) {
    for (var i = 0, elements = [], length = arguments.length; i < length; i++)
      elements.push($(arguments[i]));
    return elements;
  }
  if (Object.isString(element))
    element = document.getElementById(element);
  return Element.extend(element);
}

if (Prototype.BrowserFeatures.XPath) {
  document._getElementsByXPath = function(expression, parentElement) {
    var results = [];
    var query = document.evaluate(expression, $(parentElement) || document,
      null, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null);
    for (var i = 0, length = query.snapshotLength; i < length; i++)
      results.push(Element.extend(query.snapshotItem(i)));
    return results;
  };
}

/*--------------------------------------------------------------------------*/

if (!window.Node) var Node = { };

if (!Node.ELEMENT_NODE) {
  // DOM level 2 ECMAScript Language Binding
  Object.extend(Node, {
    ELEMENT_NODE: 1,
    ATTRIBUTE_NODE: 2,
    TEXT_NODE: 3,
    CDATA_SECTION_NODE: 4,
    ENTITY_REFERENCE_NODE: 5,
    ENTITY_NODE: 6,
    PROCESSING_INSTRUCTION_NODE: 7,
    COMMENT_NODE: 8,
    DOCUMENT_NODE: 9,
    DOCUMENT_TYPE_NODE: 10,
    DOCUMENT_FRAGMENT_NODE: 11,
    NOTATION_NODE: 12
  });
}

(function() {
  var element = this.Element;
  this.Element = function(tagName, attributes) {
    attributes = attributes || { };
    tagName = tagName.toLowerCase();
    var cache = Element.cache;
    if (Prototype.Browser.IE && attributes.name) {
      tagName = '<' + tagName + ' name="' + attributes.name + '">';
      delete attributes.name;
      return Element.writeAttribute(document.createElement(tagName), attributes);
    }
    if (!cache[tagName]) cache[tagName] = Element.extend(document.createElement(tagName));
    return Element.writeAttribute(cache[tagName].cloneNode(false), attributes);
  };
  Object.extend(this.Element, element || { });
}).call(window);

Element.cache = { };

Element.Methods = {
  
  /**
  * Returns true if the element is visible.
  * @alias Element.Methods.visible
  * @param {Object} element Element to check.
  * @return {Boolean}	Returns true if the element is visible.
  */
  visible: function(element) {
    return $(element).style.display != 'none';
  },

  /**
  * Toggles the visibility of the specified element(s).
  * @alias Element.Methods.toggle
  * @param {Object, String} One or more elements (or ids) to toggle the visibility of.
  */
  toggle: function(element) {
    element = $(element);
    Element[Element.visible(element) ? 'hide' : 'show'](element);
    return element;
  },

  /**
  * Hides the specified element(s) by setting the style.display attribute to "none".
  * @alias Element.hide
  * @param {Object} ... One or more elements to hide.
  */
  hide: function(element) {
    $(element).style.display = 'none';
    return element;
  },

  /**
  * Displays the specified element(s) by setting the style.display attribute to "".
  * @alias Element.show
  * @param {Object} ... One or more elements to display.
  */
  show: function(element) {
    $(element).style.display = '';
    return element;
  },

  /**
  * Removes the element from the document.
  * @alias Element.remove
  * @param {Object} element	Element to remove.
  */
  remove: function(element) {
    element = $(element);
    element.parentNode.removeChild(element);
    return element;
  },

  /**
  * Updates the inner HTML of the element with the specified HTML.
  * @alias Element.update
  * @param {Element} element	Element to update.
  * @param {String} html	HTML to replace the current inner HTMl with.
  */
  update: function(element, content) {
    element = $(element);
    if (content && content.toElement) content = content.toElement();
    if (Object.isElement(content)) return element.update().insert(content);
    content = Object.toHTML(content);
    element.innerHTML = content.stripScripts();
    content.evalScripts.bind(content).defer();
    return element;
  },

  /**
   * Replaces element by the content of the html argument and returns the removed element.
   * @alias Element.replace
   * @param {Element} element	Element to replace
   * @param {String} html	HTML to replace the content with.
   * @return {Element} Returns the replaced element.
   */
  replace: function(element, content) {
    element = $(element);
    if (content && content.toElement) content = content.toElement();
    else if (!Object.isElement(content)) {
      content = Object.toHTML(content);
      var range = element.ownerDocument.createRange();
      range.selectNode(element);
      content.evalScripts.bind(content).defer();
      content = range.createContextualFragment(content.stripScripts());
    }
    element.parentNode.replaceChild(content, element);
    return element;
  },

  insert: function(element, insertions) {
    element = $(element);

    if (Object.isString(insertions) || Object.isNumber(insertions) ||
        Object.isElement(insertions) || (insertions && (insertions.toElement || insertions.toHTML)))
          insertions = {bottom:insertions};

    var content, insert, tagName, childNodes;

    for (var position in insertions) {
      content  = insertions[position];
      position = position.toLowerCase();
      insert = Element._insertionTranslations[position];

      if (content && content.toElement) content = content.toElement();
      if (Object.isElement(content)) {
        insert(element, content);
        continue;
      }

      content = Object.toHTML(content);

      tagName = ((position == 'before' || position == 'after')
        ? element.parentNode : element).tagName.toUpperCase();

      childNodes = Element._getContentFromAnonymousElement(tagName, content.stripScripts());

      if (position == 'top' || position == 'after') childNodes.reverse();
      childNodes.each(insert.curry(element));

      content.evalScripts.bind(content).defer();
    }

    return element;
  },

  wrap: function(element, wrapper, attributes) {
    element = $(element);
    if (Object.isElement(wrapper))
      $(wrapper).writeAttribute(attributes || { });
    else if (Object.isString(wrapper)) wrapper = new Element(wrapper, attributes);
    else wrapper = new Element('div', wrapper);
    if (element.parentNode)
      element.parentNode.replaceChild(wrapper, element);
    wrapper.appendChild(element);
    return wrapper;
  },

  /**
   * Returns the debug-oriented string representation of element.
   * @alias Element.inspect
   * @param {Element} element Element to inspect.
   * @return {String} Returns the debug-oriented string representation of element.
   */
  inspect: function(element) {
    element = $(element);
    var result = '<' + element.tagName.toLowerCase();
    $H({'id': 'id', 'className': 'class'}).each(function(pair) {
      var property = pair.first(), attribute = pair.last();
      var value = (element[property] || '').toString();
      if (value) result += ' ' + attribute + '=' + value.inspect(true);
    });
    return result + '>';
  },

  /**
   * Recursively collects elements whose relationship is specified by property. property has to be a property (a method won't do!) of element that points to a single DOM node.
   * @alias Element.recursivelyCollect
   * @param {Element} element	Element containing the property
   * @param {String} property	Property to match
   * @return {Array}  Returns an array of extended elements.
   */
  recursivelyCollect: function(element, property) {
    element = $(element);
    var elements = [];
    while (element = element[property])
      if (element.nodeType == 1)
        elements.push(Element.extend(element));
    return elements;
  },

  /**
   * Collects all of element's ancestors and returns them as an array of extended elements.
   * @alias Element.ancestors
   * @param {Element} element Element to collect the ancestors of
   * @return {Array} Returns an array of ancestors
   */
  ancestors: function(element) {
    return $(element).recursivelyCollect('parentNode');
  },

  /**
   * Collects all of element's descendants and returns them as an array of extended elements.
   * @alias Element.descendants
   * @param {Element} element	Element to collect descendants of
   * @return {Array} Returns an array of descendants
   */
  descendants: function(element) {
    return $(element).select("*");
  },

  /**
   * Returns the first child that is an element. This is opposed to firstChild DOM property which will return any node (whitespace in most usual cases).
   * @alias Element.firstDescendant
   * @param {Element} element	Element to collect the first descendent of
   * @return {Element} Returns the first child that is an element.
   */
  firstDescendant: function(element) {
    element = $(element).firstChild;
    while (element && element.nodeType != 1) element = element.nextSibling;
    return $(element);
  },

  /**
   * Collects all of the element�s immediate descendants (i.e. children) and returns them as an array of extended elements.
   * @alias Element.immediateDescendants
   * @param {Element} element	Element to return the immediate descendants of
   * @return {Array} Returns an array of immediate descendants
   */
  immediateDescendants: function(element) {
    if (!(element = $(element).firstChild)) return [];
    while (element && element.nodeType != 1) element = element.nextSibling;
    if (element) return [element].concat($(element).nextSiblings());
    return [];
  },

  /**
   * Collects all of element's previous siblings and returns them as an array of extended elements.
   * @alias Element.previousSiblings
   * @param {Element} element Element to return the previous siblings of
   * @return {Array} Returns an array of previous siblings.
   */
  previousSiblings: function(element) {
    return $(element).recursivelyCollect('previousSibling');
  },

  /**
   * Collects all of element's next siblings and returns them as an array of extended elements.
   * @alias Element.nextSiblings
   * @param {Element} element Element to collect the next siblings of
   * @return {Array} Returns an array of next siblings.
   */
  nextSiblings: function(element) {
    return $(element).recursivelyCollect('nextSibling');
  },

  /**
   * Collects all of element's siblings and returns them as an array of extended elements.
   * @alias Element.siblings
   * @param {Element} element	Element to returns the siblings of
   * @return {Array} Returns an array of siblings
   */
  siblings: function(element) {
    element = $(element);
    return element.previousSiblings().reverse().concat(element.nextSiblings());
  },

  /**
   * Checks if the element matches the given CSS selector.
   * @alias Element.match
   * @param {Element} element	Element to match
   * @param {String} selector	CSS selector to match
   * @return {Boolean} Returns true if the element matches the given CSS selector.
   */
  match: function(element, selector) {
    if (Object.isString(selector))
      selector = new Selector(selector);
    return selector.match($(element));
  },

  /**
   * Returns element's first ancestor (or the index'th ancestor, if index is specified) that matches cssRule. If no cssRule is provided, all ancestors are considered. If no ancestor matches these criteria, undefined is returned.
   * @alias Element.up
   * @param {Element} element	Element to match
   * @param {String} [expression]	cssRule to match
   * @param {Number} [index]	Index of the ancestor, instead of using the first ancestor.
   * @return {Element} Returns the first (or index'th) ancestor of the element.
   */
  up: function(element, expression, index) {
    element = $(element);
    if (arguments.length == 1) return $(element.parentNode);
    var ancestors = element.ancestors();
    return Object.isNumber(expression) ? ancestors[expression] :
      Selector.findElement(ancestors, expression, index);
  },

  /**
   * Returns element�s first descendant (or the n-th descendant if index is specified) that matches cssRule. If no cssRule is provided, all descendants are considered. If no descendant matches these criteria, undefined is returned.
   * @alias Element.down
   * @param {Element} element	Element to match
   * @param {String} [expression]	cssRule to match
   * @param {Number} [index]	Index of the descendant, instead of using the first ancestor.
   * @return {Element} Returns the first (or index'th) descendant of the element.
   */
  down: function(element, expression, index) {
    element = $(element);
    if (arguments.length == 1) return element.firstDescendant();
    return Object.isNumber(expression) ? element.descendants()[expression] :
      element.select(expression)[index || 0];
  },

  /**
   * Returns element's previous sibling (or the index'th one, if index is specified) that matches cssRule. If no cssRule is provided, all previous siblings are considered. If no previous sibling matches these criteria, undefined is returned.
   * @alias Element.previous
   * @param {Element} element	Element to return the previous sibling of
   * @param {String} [expression]	cssRule to match
   * @param {Number} [index]	If used, specifies the index of the previous sibling to use instead of the immediate one.
   * @return {Element} Returns the previous (or specified) sibling.
   */
  previous: function(element, expression, index) {
    element = $(element);
    if (arguments.length == 1) return $(Selector.handlers.previousElementSibling(element));
    var previousSiblings = element.previousSiblings();
    return Object.isNumber(expression) ? previousSiblings[expression] :
      Selector.findElement(previousSiblings, expression, index);
  },

  /**
   * Returns element's next sibling (or the index'th one, if index is specified) that matches cssRule. If no cssRule is provided, all next siblings are considered. If no next sibling matches these criteria, undefined is returned.
   * @alias Element.next
   * @param {Element} element	Element to return the next sibling of
   * @param {String} [expression]	cssRule to match
   * @param {Number} [index]	If used, specifies the index of the next sibling to use instead of the immediate one.
   * @return {Element} Returns the next (or specified) sibling.
   */  
  next: function(element, expression, index) {
    element = $(element);
    if (arguments.length == 1) return $(Selector.handlers.nextElementSibling(element));
    var nextSiblings = element.nextSiblings();
    return Object.isNumber(expression) ? nextSiblings[expression] :
      Selector.findElement(nextSiblings, expression, index);
  },

  select: function() {
    var args = $A(arguments), element = $(args.shift());
    return Selector.findChildElements(element, args);
  },

  adjacent: function() {
    var args = $A(arguments), element = $(args.shift());
    return Selector.findChildElements(element.parentNode, args).without(element);
  },

  identify: function(element) {
    element = $(element);
    var id = element.readAttribute('id'), self = arguments.callee;
    if (id) return id;
    do { id = 'anonymous_element_' + self.counter++ } while ($(id));
    element.writeAttribute('id', id);
    return id;
  },

  /**
   * Returns the value of element's attribute or null if attribute has not been specified.
   * @alias Element.readAttribute
   * @param {Element} element	Element to read the attribute for
   * @param {String} name		Attribute of the element
   * @return {String} Returns the value of the attribute
   */
  readAttribute: function(element, name) {
    element = $(element);
    if (Prototype.Browser.IE) {
      var t = Element._attributeTranslations.read;
      if (t.values[name]) return t.values[name](element, name);
      if (t.names[name]) name = t.names[name];
      if (name.include(':')) {
        return (!element.attributes || !element.attributes[name]) ? null :
         element.attributes[name].value;
      }
    }
    return element.getAttribute(name);
  },

  writeAttribute: function(element, name, value) {
    element = $(element);
    var attributes = { }, t = Element._attributeTranslations.write;

    if (typeof name == 'object') attributes = name;
    else attributes[name] = Object.isUndefined(value) ? true : value;

    for (var attr in attributes) {
      name = t.names[attr] || attr;
      value = attributes[attr];
      if (t.values[attr]) name = t.values[attr](element, value);
      if (value === false || value === null)
        element.removeAttribute(name);
      else if (value === true)
        element.setAttribute(name, name);
      else element.setAttribute(name, value);
    }
    return element;
  },

  /**
  * Gets the offsetHeight of an element.
  * @alias Element.getHeight
  * @param {Object} element	Element to get the offsetHeight for.
  * @return {Number} Returns the offsetHeight of the element (in pixels).
  */
  getHeight: function(element) {
    return $(element).getDimensions().height;
  },

  /**
   * Finds and returns the computed width of element.
   * @alias Element.getWidth
   * @param {Element} element Element to get the width of
   * @return {Number} Returns the width of the element.
   */
  getWidth: function(element) {
    return $(element).getDimensions().width;
  },

  /**
  * Gets the CSS class names associated with an element.
  * @alias Element.classNames
  * @param {Object} element	Element to get the associated class names for.
  * @return {Object} Returns an Element.ClassNames object representing the class names.
  */
  classNames: function(element) {
    return new Element.ClassNames(element);
  },

  /**
  * Returns true if the element has the specified CSS class name.
  * @alias Element.hasClassName()
  * @param {Object} element	Element to get the class name for.
  * @param {Object} className	Class name to check for.
  * @return {Boolean} Returns true if the element has the specified CSS class name.
  */
  hasClassName: function(element, className) {
    if (!(element = $(element))) return;
    var elementClassName = element.className;
    return (elementClassName.length > 0 && (elementClassName == className ||
      new RegExp("(^|\\s)" + className + "(\\s|$)").test(elementClassName)));
  },

  /**
  * Adds the specified class to the list of class names for the element.
  * @alias Element.addClassName
  * @param {Object, String} element	Element or id to add the class name to.
  * @param {String} className	CSS class name to add.
  */
  addClassName: function(element, className) {
    if (!(element = $(element))) return;
    if (!element.hasClassName(className))
      element.className += (element.className ? ' ' : '') + className;
    return element;
  },

  /**
  * Removes the specified CSS class name from the element.
  * @alias Element.removeClassName
  * @param {Object} element	Element to remove the class name from.
  * @param {Object} className	Class name to remove.
  */
  removeClassName: function(element, className) {
    if (!(element = $(element))) return;
    element.className = element.className.replace(
      new RegExp("(^|\\s+)" + className + "(\\s+|$)"), ' ').strip();
    return element;
  },

  /**
   * Toggles element's CSS className and returns element.
   * @alias Element.toggleClassName
   * @param {Element} element	Element to toggle
   * @param {String} className	CSS class name
   * @return {Element} Returns the element.
   */
  toggleClassName: function(element, className) {
    if (!(element = $(element))) return;
    return element[element.hasClassName(className) ?
      'removeClassName' : 'addClassName'](className);
  },

  // removes whitespace-only text node children

  /**
  * Removes any whitespace from the text of the child nodes of the element.
  * @alias Element.cleanWhitespace
  * @param {Object} element Element to clean the whitespace for.
  * @return {Element} Returns the element.
  */
  cleanWhitespace: function(element) {
    element = $(element);
    var node = element.firstChild;
    while (node) {
      var nextNode = node.nextSibling;
      if (node.nodeType == 3 && !/\S/.test(node.nodeValue))
        element.removeChild(node);
      node = nextNode;
    }
    return element;
  },

 /**
 * Returns true if the element is empty or contains only whitespace.
 * @alias Element.empty
 * @param {Object} element	Element to check.
 * @return {Boolean} Returns true if the element is empty or contains only whitespace.
 */
  empty: function(element) {
    return $(element).innerHTML.blank();
  },

  /**
   * Checks if element is a descendant of ancestor.
   * @alias Element.descendantOf
   * @param {Element} element	Element to check
   * @param {Element} ancestor	Ancestor element to check
   * @return {Boolean} Returns true if element is a descendant of ancestor.
   */
  descendantOf: function(element, ancestor) {
    element = $(element), ancestor = $(ancestor);
    var originalAncestor = ancestor;

    if (element.compareDocumentPosition)
      return (element.compareDocumentPosition(ancestor) & 8) === 8;

    if (element.sourceIndex && !Prototype.Browser.Opera) {
      var e = element.sourceIndex, a = ancestor.sourceIndex,
       nextAncestor = ancestor.nextSibling;
      if (!nextAncestor) {
        do { ancestor = ancestor.parentNode; }
        while (!(nextAncestor = ancestor.nextSibling) && ancestor.parentNode);
      }
      if (nextAncestor && nextAncestor.sourceIndex)
       return (e > a && e < nextAncestor.sourceIndex);
    }

    while (element = element.parentNode)
      if (element == originalAncestor) return true;
    return false;
  },

  /**
  * Scrolls the window to the position of the specified element.
  * @alias Element.scrollTo
  * @param {Object} element	Element to scroll to.
  */
  scrollTo: function(element) {
    element = $(element);
    var pos = element.cumulativeOffset();
    window.scrollTo(pos[0], pos[1]);
    return element;
  },

  /**
  * Gets the value of the specified CSS style attribute for the element.
  * @alias Element.getStyle
  * @param {Object} element	Element to get the style for.
  * @param {String} style	Name of the CSS style.
  * @return {String, Number, Boolean, Array, Object} Returns the value of the CSS style attribute.
  */
  getStyle: function(element, style) {
    element = $(element);
    style = style == 'float' ? 'cssFloat' : style.camelize();
    var value = element.style[style];
    if (!value) {
      var css = document.defaultView.getComputedStyle(element, null);
      value = css ? css[style] : null;
    }
    if (style == 'opacity') return value ? parseFloat(value) : 1.0;
    return value == 'auto' ? null : value;
  },

  /**
   * Returns the value for the opacity of the element.
   * @alias Element.getOpacity
   * @param {Element} element	Element to find the opacity of
   * @return {Number} Returns the opacity value.
   */
  getOpacity: function(element) {
    return $(element).getStyle('opacity');
  },

  /**
  * Sets the value of the specified CSS element.
  * @alias Element.setStyle
  * @param {Object} element	Element to apply the style to.
  * @param {Object} style	Style to apply.
  */
  setStyle: function(element, styles) {
    element = $(element);
    var elementStyle = element.style, match;
    if (Object.isString(styles)) {
      element.style.cssText += ';' + styles;
      return styles.include('opacity') ?
        element.setOpacity(styles.match(/opacity:\s*(\d?\.?\d*)/)[1]) : element;
    }
    for (var property in styles)
      if (property == 'opacity') element.setOpacity(styles[property]);
      else
        elementStyle[(property == 'float' || property == 'cssFloat') ?
          (Object.isUndefined(elementStyle.styleFloat) ? 'cssFloat' : 'styleFloat') :
            property] = styles[property];

    return element;
  },

  /**
   * Sets the opacity value for the element.
   * @alias Element.setOpacity
   * @param {Element} element	Element to set
   * @param {Number} value	Opacity value
   * @return {Element} Returns the element with the new opacity value set.
   */
  setOpacity: function(element, value) {
    element = $(element);
    element.style.opacity = (value == 1 || value === '') ? '' :
      (value < 0.00001) ? 0 : value;
    return element;
  },

  /**
  * Gets the width and height of an element.
  * @alias Element.getDimensions
  * @param {Object} element	Element to get the dimensions for.
  * @return {String} Returns the width and height of the element.
  */
  getDimensions: function(element) {
    element = $(element);
    var display = $(element).getStyle('display');
    if (display != 'none' && display != null) // Safari bug
      return {width: element.offsetWidth, height: element.offsetHeight};

    // All *Width and *Height properties give 0 on elements with display none,
    // so enable the element temporarily
    var els = element.style;
    var originalVisibility = els.visibility;
    var originalPosition = els.position;
    var originalDisplay = els.display;
    els.visibility = 'hidden';
    els.position = 'absolute';
    els.display = 'block';
    var originalWidth = element.clientWidth;
    var originalHeight = element.clientHeight;
    els.display = originalDisplay;
    els.position = originalPosition;
    els.visibility = originalVisibility;
    return {width: originalWidth, height: originalHeight};
  },

  /**
  * Sets the style.position attribute for the element to "relative".
  * @alias Element.makePositioned
  * @param {Object} element	Element to set the position attribute for.
  */
  makePositioned: function(element) {
    element = $(element);
    var pos = Element.getStyle(element, 'position');
    if (pos == 'static' || !pos) {
      element._madePositioned = true;
      element.style.position = 'relative';
      // Opera returns the offset relative to the positioning context, when an
      // element is position relative but top and left have not been defined
      if (window.opera) {
        element.style.top = 0;
        element.style.left = 0;
      }
    }
    return element;
  },

  /**
  * Clears the style.position attribute for the element to "".
  * @alias Element.undoPositioned
  * @param {Object} element	Element to set the position attribute for.
  */
  undoPositioned: function(element) {
    element = $(element);
    if (element._madePositioned) {
      element._madePositioned = undefined;
      element.style.position =
        element.style.top =
        element.style.left =
        element.style.bottom =
        element.style.right = '';
    }
    return element;
  },

  /**
  * Clips the overflow of the specified element so that it is not visible.
  * @alias Element.makeClipping
  * @param {Object} element	Element to clip the overflow for.
  */
  makeClipping: function(element) {
    element = $(element);
    if (element._overflow) return element;
    element._overflow = Element.getStyle(element, 'overflow') || 'auto';
    if (element._overflow !== 'hidden')
      element.style.overflow = 'hidden';
    return element;
  },

  /**
  * Undoes the overflow clipping of the specified element so that it is visible.
  * @alias Element.undoClipping
  * @param {Object} element	Element to display the overflow for.
  */
  undoClipping: function(element) {
    element = $(element);
    if (!element._overflow) return element;
    element.style.overflow = element._overflow == 'auto' ? '' : element._overflow;
    element._overflow = null;
    return element;
  },

  cumulativeOffset: function(element) {
    var valueT = 0, valueL = 0;
    do {
      valueT += element.offsetTop  || 0;
      valueL += element.offsetLeft || 0;
      element = element.offsetParent;
    } while (element);
    return Element._returnOffset(valueL, valueT);
  },

  positionedOffset: function(element) {
    var valueT = 0, valueL = 0;
    do {
      valueT += element.offsetTop  || 0;
      valueL += element.offsetLeft || 0;
      element = element.offsetParent;
      if (element) {
        if (element.tagName == 'BODY') break;
        var p = Element.getStyle(element, 'position');
        if (p !== 'static') break;
      }
    } while (element);
    return Element._returnOffset(valueL, valueT);
  },

  absolutize: function(element) {
    element = $(element);
    if (element.getStyle('position') == 'absolute') return;
    // Position.prepare(); // To be done manually by Scripty when it needs it.

    var offsets = element.positionedOffset();
    var top     = offsets[1];
    var left    = offsets[0];
    var width   = element.clientWidth;
    var height  = element.clientHeight;

    element._originalLeft   = left - parseFloat(element.style.left  || 0);
    element._originalTop    = top  - parseFloat(element.style.top || 0);
    element._originalWidth  = element.style.width;
    element._originalHeight = element.style.height;

    element.style.position = 'absolute';
    element.style.top    = top + 'px';
    element.style.left   = left + 'px';
    element.style.width  = width + 'px';
    element.style.height = height + 'px';
    return element;
  },

  relativize: function(element) {
    element = $(element);
    if (element.getStyle('position') == 'relative') return;
    // Position.prepare(); // To be done manually by Scripty when it needs it.

    element.style.position = 'relative';
    var top  = parseFloat(element.style.top  || 0) - (element._originalTop || 0);
    var left = parseFloat(element.style.left || 0) - (element._originalLeft || 0);

    element.style.top    = top + 'px';
    element.style.left   = left + 'px';
    element.style.height = element._originalHeight;
    element.style.width  = element._originalWidth;
    return element;
  },

  cumulativeScrollOffset: function(element) {
    var valueT = 0, valueL = 0;
    do {
      valueT += element.scrollTop  || 0;
      valueL += element.scrollLeft || 0;
      element = element.parentNode;
    } while (element);
    return Element._returnOffset(valueL, valueT);
  },

  getOffsetParent: function(element) {
    if (element.offsetParent) return $(element.offsetParent);
    if (element == document.body) return $(element);

    while ((element = element.parentNode) && element != document.body)
      if (Element.getStyle(element, 'position') != 'static')
        return $(element);

    return $(document.body);
  },

  viewportOffset: function(forElement) {
    var valueT = 0, valueL = 0;

    var element = forElement;
    do {
      valueT += element.offsetTop  || 0;
      valueL += element.offsetLeft || 0;

      // Safari fix
      if (element.offsetParent == document.body &&
        Element.getStyle(element, 'position') == 'absolute') break;

    } while (element = element.offsetParent);

    element = forElement;
    do {
      if (!Prototype.Browser.Opera || element.tagName == 'BODY') {
        valueT -= element.scrollTop  || 0;
        valueL -= element.scrollLeft || 0;
      }
    } while (element = element.parentNode);

    return Element._returnOffset(valueL, valueT);
  },

  clonePosition: function(element, source) {
    var options = Object.extend({
      setLeft:    true,
      setTop:     true,
      setWidth:   true,
      setHeight:  true,
      offsetTop:  0,
      offsetLeft: 0
    }, arguments[2] || { });

    // find page position of source
    source = $(source);
    var p = source.viewportOffset();

    // find coordinate system to use
    element = $(element);
    var delta = [0, 0];
    var parent = null;
    // delta [0,0] will do fine with position: fixed elements,
    // position:absolute needs offsetParent deltas
    if (Element.getStyle(element, 'position') == 'absolute') {
      parent = element.getOffsetParent();
      delta = parent.viewportOffset();
    }

    // correct by body offsets (fixes Safari)
    if (parent == document.body) {
      delta[0] -= document.body.offsetLeft;
      delta[1] -= document.body.offsetTop;
    }

    // set position
    if (options.setLeft)   element.style.left  = (p[0] - delta[0] + options.offsetLeft) + 'px';
    if (options.setTop)    element.style.top   = (p[1] - delta[1] + options.offsetTop) + 'px';
    if (options.setWidth)  element.style.width = source.offsetWidth + 'px';
    if (options.setHeight) element.style.height = source.offsetHeight + 'px';
    return element;
  }
};

Element.Methods.identify.counter = 1;

Object.extend(Element.Methods, {
  getElementsBySelector: Element.Methods.select,
  childElements: Element.Methods.immediateDescendants
});

Element._attributeTranslations = {
  write: {
    names: {
      className: 'class',
      htmlFor:   'for'
    },
    values: { }
  }
};

if (Prototype.Browser.Opera) {
  Element.Methods.getStyle = Element.Methods.getStyle.wrap(
    function(proceed, element, style) {
      switch (style) {
        case 'left': case 'top': case 'right': case 'bottom':
          if (proceed(element, 'position') === 'static') return null;
        case 'height': case 'width':
          // returns '0px' for hidden elements; we want it to return null
          if (!Element.visible(element)) return null;

          // returns the border-box dimensions rather than the content-box
          // dimensions, so we subtract padding and borders from the value
          var dim = parseInt(proceed(element, style), 10);

          if (dim !== element['offset' + style.capitalize()])
            return dim + 'px';

          var properties;
          if (style === 'height') {
            properties = ['border-top-width', 'padding-top',
             'padding-bottom', 'border-bottom-width'];
          }
          else {
            properties = ['border-left-width', 'padding-left',
             'padding-right', 'border-right-width'];
          }
          return properties.inject(dim, function(memo, property) {
            var val = proceed(element, property);
            return val === null ? memo : memo - parseInt(val, 10);
          }) + 'px';
        default: return proceed(element, style);
      }
    }
  );

  Element.Methods.readAttribute = Element.Methods.readAttribute.wrap(
    function(proceed, element, attribute) {
      if (attribute === 'title') return element.title;
      return proceed(element, attribute);
    }
  );
}

else if (Prototype.Browser.IE) {
  // IE doesn't report offsets correctly for static elements, so we change them
  // to "relative" to get the values, then change them back.
  Element.Methods.getOffsetParent = Element.Methods.getOffsetParent.wrap(
    function(proceed, element) {
      element = $(element);
      var position = element.getStyle('position');
      if (position !== 'static') return proceed(element);
      element.setStyle({ position: 'relative' });
      var value = proceed(element);
      element.setStyle({ position: position });
      return value;
    }
  );

  $w('positionedOffset viewportOffset').each(function(method) {
    Element.Methods[method] = Element.Methods[method].wrap(
      function(proceed, element) {
        element = $(element);
        var position = element.getStyle('position');
        if (position !== 'static') return proceed(element);
        // Trigger hasLayout on the offset parent so that IE6 reports
        // accurate offsetTop and offsetLeft values for position: fixed.
        var offsetParent = element.getOffsetParent();
        if (offsetParent && offsetParent.getStyle('position') === 'fixed')
          offsetParent.setStyle({ zoom: 1 });
        element.setStyle({ position: 'relative' });
        var value = proceed(element);
        element.setStyle({ position: position });
        return value;
      }
    );
  });

  Element.Methods.getStyle = function(element, style) {
    element = $(element);
    style = (style == 'float' || style == 'cssFloat') ? 'styleFloat' : style.camelize();
    var value = element.style[style];
    if (!value && element.currentStyle) value = element.currentStyle[style];

    if (style == 'opacity') {
      if (value = (element.getStyle('filter') || '').match(/alpha\(opacity=(.*)\)/))
        if (value[1]) return parseFloat(value[1]) / 100;
      return 1.0;
    }

    if (value == 'auto') {
      if ((style == 'width' || style == 'height') && (element.getStyle('display') != 'none'))
        return element['offset' + style.capitalize()] + 'px';
      return null;
    }
    return value;
  };

  Element.Methods.setOpacity = function(element, value) {
    function stripAlpha(filter){
      return filter.replace(/alpha\([^\)]*\)/gi,'');
    }
    element = $(element);
    var currentStyle = element.currentStyle;
    if ((currentStyle && !currentStyle.hasLayout) ||
      (!currentStyle && element.style.zoom == 'normal'))
        element.style.zoom = 1;

    var filter = element.getStyle('filter'), style = element.style;
    if (value == 1 || value === '') {
      (filter = stripAlpha(filter)) ?
        style.filter = filter : style.removeAttribute('filter');
      return element;
    } else if (value < 0.00001) value = 0;
    style.filter = stripAlpha(filter) +
      'alpha(opacity=' + (value * 100) + ')';
    return element;
  };

  Element._attributeTranslations = {
    read: {
      names: {
        'class': 'className',
        'for':   'htmlFor'
      },
      values: {
        _getAttr: function(element, attribute) {
          return element.getAttribute(attribute, 2);
        },
        _getAttrNode: function(element, attribute) {
          var node = element.getAttributeNode(attribute);
          return node ? node.value : "";
        },
        _getEv: function(element, attribute) {
          attribute = element.getAttribute(attribute);
          return attribute ? attribute.toString().slice(23, -2) : null;
        },
        _flag: function(element, attribute) {
          return $(element).hasAttribute(attribute) ? attribute : null;
        },
        style: function(element) {
          return element.style.cssText.toLowerCase();
        },
        title: function(element) {
          return element.title;
        }
      }
    }
  };

  Element._attributeTranslations.write = {
    names: Object.extend({
      cellpadding: 'cellPadding',
      cellspacing: 'cellSpacing'
    }, Element._attributeTranslations.read.names),
    values: {
      checked: function(element, value) {
        element.checked = !!value;
      },

      style: function(element, value) {
        element.style.cssText = value ? value : '';
      }
    }
  };

  Element._attributeTranslations.has = {};

  $w('colSpan rowSpan vAlign dateTime accessKey tabIndex ' +
      'encType maxLength readOnly longDesc').each(function(attr) {
    Element._attributeTranslations.write.names[attr.toLowerCase()] = attr;
    Element._attributeTranslations.has[attr.toLowerCase()] = attr;
  });

  (function(v) {
    Object.extend(v, {
      href:        v._getAttr,
      src:         v._getAttr,
      type:        v._getAttr,
      action:      v._getAttrNode,
      disabled:    v._flag,
      checked:     v._flag,
      readonly:    v._flag,
      multiple:    v._flag,
      onload:      v._getEv,
      onunload:    v._getEv,
      onclick:     v._getEv,
      ondblclick:  v._getEv,
      onmousedown: v._getEv,
      onmouseup:   v._getEv,
      onmouseover: v._getEv,
      onmousemove: v._getEv,
      onmouseout:  v._getEv,
      onfocus:     v._getEv,
      onblur:      v._getEv,
      onkeypress:  v._getEv,
      onkeydown:   v._getEv,
      onkeyup:     v._getEv,
      onsubmit:    v._getEv,
      onreset:     v._getEv,
      onselect:    v._getEv,
      onchange:    v._getEv
    });
  })(Element._attributeTranslations.read.values);
}

else if (Prototype.Browser.Gecko && /rv:1\.8\.0/.test(navigator.userAgent)) {
  Element.Methods.setOpacity = function(element, value) {
    element = $(element);
    element.style.opacity = (value == 1) ? 0.999999 :
      (value === '') ? '' : (value < 0.00001) ? 0 : value;
    return element;
  };
}

else if (Prototype.Browser.WebKit) {
  Element.Methods.setOpacity = function(element, value) {
    element = $(element);
    element.style.opacity = (value == 1 || value === '') ? '' :
      (value < 0.00001) ? 0 : value;

    if (value == 1)
      if(element.tagName == 'IMG' && element.width) {
        element.width++; element.width--;
      } else try {
        var n = document.createTextNode(' ');
        element.appendChild(n);
        element.removeChild(n);
      } catch (e) { }

    return element;
  };

  // Safari returns margins on body which is incorrect if the child is absolutely
  // positioned.  For performance reasons, redefine Element#cumulativeOffset for
  // KHTML/WebKit only.
  Element.Methods.cumulativeOffset = function(element) {
    var valueT = 0, valueL = 0;
    do {
      valueT += element.offsetTop  || 0;
      valueL += element.offsetLeft || 0;
      if (element.offsetParent == document.body)
        if (Element.getStyle(element, 'position') == 'absolute') break;

      element = element.offsetParent;
    } while (element);

    return Element._returnOffset(valueL, valueT);
  };
}

if (Prototype.Browser.IE || Prototype.Browser.Opera) {
  // IE and Opera are missing .innerHTML support for TABLE-related and SELECT elements
  
  /**
   * Replaces the content of element with the provided newContent argument and returns element.
   * @alias Element.Methods.update
   * @param {Element} element	Element to update
   * @param {String} html	New HTML content
   * @return {Element} Returns the updated element.
   */
  Element.Methods.update = function(element, content) {
    element = $(element);

    if (content && content.toElement) content = content.toElement();
    if (Object.isElement(content)) return element.update().insert(content);

    content = Object.toHTML(content);
    var tagName = element.tagName.toUpperCase();

    if (tagName in Element._insertionTranslations.tags) {
      $A(element.childNodes).each(function(node) { element.removeChild(node) });
      Element._getContentFromAnonymousElement(tagName, content.stripScripts())
        .each(function(node) { element.appendChild(node) });
    }
    else element.innerHTML = content.stripScripts();

    content.evalScripts.bind(content).defer();
    return element;
  };
}

if ('outerHTML' in document.createElement('div')) {
  Element.Methods.replace = function(element, content) {
    element = $(element);

    if (content && content.toElement) content = content.toElement();
    if (Object.isElement(content)) {
      element.parentNode.replaceChild(content, element);
      return element;
    }

    content = Object.toHTML(content);
    var parent = element.parentNode, tagName = parent.tagName.toUpperCase();

    if (Element._insertionTranslations.tags[tagName]) {
      var nextSibling = element.next();
      var fragments = Element._getContentFromAnonymousElement(tagName, content.stripScripts());
      parent.removeChild(element);
      if (nextSibling)
        fragments.each(function(node) { parent.insertBefore(node, nextSibling) });
      else
        fragments.each(function(node) { parent.appendChild(node) });
    }
    else element.outerHTML = content.stripScripts();

    content.evalScripts.bind(content).defer();
    return element;
  };
}

Element._returnOffset = function(l, t) {
  var result = [l, t];
  result.left = l;
  result.top = t;
  return result;
};

Element._getContentFromAnonymousElement = function(tagName, html) {
  var div = new Element('div'), t = Element._insertionTranslations.tags[tagName];
  if (t) {
    div.innerHTML = t[0] + html + t[1];
    t[2].times(function() { div = div.firstChild });
  } else div.innerHTML = html;
  return $A(div.childNodes);
};

Element._insertionTranslations = {
  before: function(element, node) {
    element.parentNode.insertBefore(node, element);
  },
  top: function(element, node) {
    element.insertBefore(node, element.firstChild);
  },
  bottom: function(element, node) {
    element.appendChild(node);
  },
  after: function(element, node) {
    element.parentNode.insertBefore(node, element.nextSibling);
  },
  tags: {
    TABLE:  ['<table>',                '</table>',                   1],
    TBODY:  ['<table><tbody>',         '</tbody></table>',           2],
    TR:     ['<table><tbody><tr>',     '</tr></tbody></table>',      3],
    TD:     ['<table><tbody><tr><td>', '</td></tr></tbody></table>', 4],
    SELECT: ['<select>',               '</select>',                  1]
  }
};

(function() {
  Object.extend(this.tags, {
    THEAD: this.tags.TBODY,
    TFOOT: this.tags.TBODY,
    TH:    this.tags.TD
  });
}).call(Element._insertionTranslations);

Element.Methods.Simulated = {
  hasAttribute: function(element, attribute) {
    attribute = Element._attributeTranslations.has[attribute] || attribute;
    var node = $(element).getAttributeNode(attribute);
    return node && node.specified;
  }
};

Element.Methods.ByTag = { };

Object.extend(Element, Element.Methods);

if (!Prototype.BrowserFeatures.ElementExtensions &&
    document.createElement('div').__proto__) {
  window.HTMLElement = { };
  window.HTMLElement.prototype = document.createElement('div').__proto__;
  Prototype.BrowserFeatures.ElementExtensions = true;
}

Element.extend = (function() {
  if (Prototype.BrowserFeatures.SpecificElementExtensions)
    return Prototype.K;

  var Methods = { }, ByTag = Element.Methods.ByTag;

  var extend = Object.extend(function(element) {
    if (!element || element._extendedByPrototype ||
        element.nodeType != 1 || element == window) return element;

    var methods = Object.clone(Methods),
      tagName = element.tagName, property, value;

    // extend methods for specific tags
    if (ByTag[tagName]) Object.extend(methods, ByTag[tagName]);

    for (property in methods) {
      value = methods[property];
      if (Object.isFunction(value) && !(property in element))
        element[property] = value.methodize();
    }

    element._extendedByPrototype = Prototype.emptyFunction;
    return element;

  }, {
    refresh: function() {
      // extend methods for all tags (Safari doesn't need this)
      if (!Prototype.BrowserFeatures.ElementExtensions) {
        Object.extend(Methods, Element.Methods);
        Object.extend(Methods, Element.Methods.Simulated);
      }
    }
  });

  extend.refresh();
  return extend;
})();

/**
 * Simulates the standard compliant DOM method hasAttribute for browsers missing it (Internet Explorer 6 and 7).
 * @alias Element.Methods.Simulated.hasAttribute
 * @param {Element} element	Element to check
 * @param {Attribute} attribute Attribute to check for
 * @return {Boolean} Returns true if the element has the specified attribute.
 */
Element.hasAttribute = function(element, attribute) {
  if (element.hasAttribute) return element.hasAttribute(attribute);
  return Element.Methods.Simulated.hasAttribute(element, attribute);
};

Element.addMethods = function(methods) {
  var F = Prototype.BrowserFeatures, T = Element.Methods.ByTag;

  if (!methods) {
    Object.extend(Form, Form.Methods);
    Object.extend(Form.Element, Form.Element.Methods);
    Object.extend(Element.Methods.ByTag, {
      "FORM":     Object.clone(Form.Methods),
      "INPUT":    Object.clone(Form.Element.Methods),
      "SELECT":   Object.clone(Form.Element.Methods),
      "TEXTAREA": Object.clone(Form.Element.Methods)
    });
  }

  if (arguments.length == 2) {
    var tagName = methods;
    methods = arguments[1];
  }

  if (!tagName) Object.extend(Element.Methods, methods || { });
  else {
    if (Object.isArray(tagName)) tagName.each(extend);
    else extend(tagName);
  }

  function extend(tagName) {
    tagName = tagName.toUpperCase();
    if (!Element.Methods.ByTag[tagName])
      Element.Methods.ByTag[tagName] = { };
    Object.extend(Element.Methods.ByTag[tagName], methods);
  }

  function copy(methods, destination, onlyIfAbsent) {
    onlyIfAbsent = onlyIfAbsent || false;
    for (var property in methods) {
      var value = methods[property];
      if (!Object.isFunction(value)) continue;
      if (!onlyIfAbsent || !(property in destination))
        destination[property] = value.methodize();
    }
  }

  function findDOMClass(tagName) {
    var klass;
    var trans = {
      "OPTGROUP": "OptGroup", "TEXTAREA": "TextArea", "P": "Paragraph",
      "FIELDSET": "FieldSet", "UL": "UList", "OL": "OList", "DL": "DList",
      "DIR": "Directory", "H1": "Heading", "H2": "Heading", "H3": "Heading",
      "H4": "Heading", "H5": "Heading", "H6": "Heading", "Q": "Quote",
      "INS": "Mod", "DEL": "Mod", "A": "Anchor", "IMG": "Image", "CAPTION":
      "TableCaption", "COL": "TableCol", "COLGROUP": "TableCol", "THEAD":
      "TableSection", "TFOOT": "TableSection", "TBODY": "TableSection", "TR":
      "TableRow", "TH": "TableCell", "TD": "TableCell", "FRAMESET":
      "FrameSet", "IFRAME": "IFrame"
    };
    if (trans[tagName]) klass = 'HTML' + trans[tagName] + 'Element';
    if (window[klass]) return window[klass];
    klass = 'HTML' + tagName + 'Element';
    if (window[klass]) return window[klass];
    klass = 'HTML' + tagName.capitalize() + 'Element';
    if (window[klass]) return window[klass];

    window[klass] = { };
    window[klass].prototype = document.createElement(tagName).__proto__;
    return window[klass];
  }

  if (F.ElementExtensions) {
    copy(Element.Methods, HTMLElement.prototype);
    copy(Element.Methods.Simulated, HTMLElement.prototype, true);
  }

  if (F.SpecificElementExtensions) {
    for (var tag in Element.Methods.ByTag) {
      var klass = findDOMClass(tag);
      if (Object.isUndefined(klass)) continue;
      copy(T[tag], klass.prototype);
    }
  }

  Object.extend(Element, Element.Methods);
  delete Element.ByTag;

  if (Element.extend.refresh) Element.extend.refresh();
  Element.cache = { };
};

document.viewport = {
  getDimensions: function() {
    var dimensions = { };
    var B = Prototype.Browser;
    $w('width height').each(function(d) {
      var D = d.capitalize();
      dimensions[d] = (B.WebKit && !document.evaluate) ? self['inner' + D] :
        (B.Opera) ? document.body['client' + D] : document.documentElement['client' + D];
    });
    return dimensions;
  },

  getWidth: function() {
    return this.getDimensions().width;
  },

  getHeight: function() {
    return this.getDimensions().height;
  },

  getScrollOffsets: function() {
    return Element._returnOffset(
      window.pageXOffset || document.documentElement.scrollLeft || document.body.scrollLeft,
      window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop);
  }
};
/* Portions of the Selector class are derived from Jack Slocum’s DomQuery,
 * part of YUI-Ext version 0.40, distributed under the terms of an MIT-style
 * license.  Please see http://www.yui-ext.com/ for more information. */

var Selector = Class.create({
  initialize: function(expression) {
    this.expression = expression.strip();
    this.compileMatcher();
  },

  shouldUseXPath: function() {
    if (!Prototype.BrowserFeatures.XPath) return false;

    var e = this.expression;

    // Safari 3 chokes on :*-of-type and :empty
    if (Prototype.Browser.WebKit &&
     (e.include("-of-type") || e.include(":empty")))
      return false;

    // XPath can't do namespaced attributes, nor can it read
    // the "checked" property from DOM nodes
    if ((/(\[[\w-]*?:|:checked)/).test(this.expression))
      return false;

    return true;
  },

  compileMatcher: function() {
    if (this.shouldUseXPath())
      return this.compileXPathMatcher();

    var e = this.expression, ps = Selector.patterns, h = Selector.handlers,
        c = Selector.criteria, le, p, m;

    if (Selector._cache[e]) {
      this.matcher = Selector._cache[e];
      return;
    }

    this.matcher = ["this.matcher = function(root) {",
                    "var r = root, h = Selector.handlers, c = false, n;"];

    while (e && le != e && (/\S/).test(e)) {
      le = e;
      for (var i in ps) {
        p = ps[i];
        if (m = e.match(p)) {
          this.matcher.push(Object.isFunction(c[i]) ? c[i](m) :
    	      new Template(c[i]).evaluate(m));
          e = e.replace(m[0], '');
          break;
        }
      }
    }

    this.matcher.push("return h.unique(n);\n}");
    eval(this.matcher.join('\n'));
    Selector._cache[this.expression] = this.matcher;
  },

  compileXPathMatcher: function() {
    var e = this.expression, ps = Selector.patterns,
        x = Selector.xpath, le, m;

    if (Selector._cache[e]) {
      this.xpath = Selector._cache[e]; return;
    }

    this.matcher = ['.//*'];
    while (e && le != e && (/\S/).test(e)) {
      le = e;
      for (var i in ps) {
        if (m = e.match(ps[i])) {
          this.matcher.push(Object.isFunction(x[i]) ? x[i](m) :
            new Template(x[i]).evaluate(m));
          e = e.replace(m[0], '');
          break;
        }
      }
    }

    this.xpath = this.matcher.join('');
    Selector._cache[this.expression] = this.xpath;
  },

  findElements: function(root) {
    root = root || document;
    if (this.xpath) return document._getElementsByXPath(this.xpath, root);
    return this.matcher(root);
  },

  match: function(element) {
    this.tokens = [];

    var e = this.expression, ps = Selector.patterns, as = Selector.assertions;
    var le, p, m;

    while (e && le !== e && (/\S/).test(e)) {
      le = e;
      for (var i in ps) {
        p = ps[i];
        if (m = e.match(p)) {
          // use the Selector.assertions methods unless the selector
          // is too complex.
          if (as[i]) {
            this.tokens.push([i, Object.clone(m)]);
            e = e.replace(m[0], '');
          } else {
            // reluctantly do a document-wide search
            // and look for a match in the array
            return this.findElements(document).include(element);
          }
        }
      }
    }

    var match = true, name, matches;
    for (var i = 0, token; token = this.tokens[i]; i++) {
      name = token[0], matches = token[1];
      if (!Selector.assertions[name](element, matches)) {
        match = false; break;
      }
    }

    return match;
  },

  toString: function() {
    return this.expression;
  },

  inspect: function() {
    return "#<Selector:" + this.expression.inspect() + ">";
  }
});

Object.extend(Selector, {
  _cache: { },

  xpath: {
    descendant:   "//*",
    child:        "/*",
    adjacent:     "/following-sibling::*[1]",
    laterSibling: '/following-sibling::*',
    tagName:      function(m) {
      if (m[1] == '*') return '';
      return "[local-name()='" + m[1].toLowerCase() +
             "' or local-name()='" + m[1].toUpperCase() + "']";
    },
    className:    "[contains(concat(' ', @class, ' '), ' #{1} ')]",
    id:           "[@id='#{1}']",
    attrPresence: function(m) {
      m[1] = m[1].toLowerCase();
      return new Template("[@#{1}]").evaluate(m);
    },
    attr: function(m) {
      m[1] = m[1].toLowerCase();
      m[3] = m[5] || m[6];
      return new Template(Selector.xpath.operators[m[2]]).evaluate(m);
    },
    pseudo: function(m) {
      var h = Selector.xpath.pseudos[m[1]];
      if (!h) return '';
      if (Object.isFunction(h)) return h(m);
      return new Template(Selector.xpath.pseudos[m[1]]).evaluate(m);
    },
    operators: {
      '=':  "[@#{1}='#{3}']",
      '!=': "[@#{1}!='#{3}']",
      '^=': "[starts-with(@#{1}, '#{3}')]",
      '$=': "[substring(@#{1}, (string-length(@#{1}) - string-length('#{3}') + 1))='#{3}']",
      '*=': "[contains(@#{1}, '#{3}')]",
      '~=': "[contains(concat(' ', @#{1}, ' '), ' #{3} ')]",
      '|=': "[contains(concat('-', @#{1}, '-'), '-#{3}-')]"
    },
    pseudos: {
      'first-child': '[not(preceding-sibling::*)]',
      'last-child':  '[not(following-sibling::*)]',
      'only-child':  '[not(preceding-sibling::* or following-sibling::*)]',
      'empty':       "[count(*) = 0 and (count(text()) = 0 or translate(text(), ' \t\r\n', '') = '')]",
      'checked':     "[@checked]",
      'disabled':    "[@disabled]",
      'enabled':     "[not(@disabled)]",
      'not': function(m) {
        var e = m[6], p = Selector.patterns,
            x = Selector.xpath, le, v;

        var exclusion = [];
        while (e && le != e && (/\S/).test(e)) {
          le = e;
          for (var i in p) {
            if (m = e.match(p[i])) {
              v = Object.isFunction(x[i]) ? x[i](m) : new Template(x[i]).evaluate(m);
              exclusion.push("(" + v.substring(1, v.length - 1) + ")");
              e = e.replace(m[0], '');
              break;
            }
          }
        }
        return "[not(" + exclusion.join(" and ") + ")]";
      },
      'nth-child':      function(m) {
        return Selector.xpath.pseudos.nth("(count(./preceding-sibling::*) + 1) ", m);
      },
      'nth-last-child': function(m) {
        return Selector.xpath.pseudos.nth("(count(./following-sibling::*) + 1) ", m);
      },
      'nth-of-type':    function(m) {
        return Selector.xpath.pseudos.nth("position() ", m);
      },
      'nth-last-of-type': function(m) {
        return Selector.xpath.pseudos.nth("(last() + 1 - position()) ", m);
      },
      'first-of-type':  function(m) {
        m[6] = "1"; return Selector.xpath.pseudos['nth-of-type'](m);
      },
      'last-of-type':   function(m) {
        m[6] = "1"; return Selector.xpath.pseudos['nth-last-of-type'](m);
      },
      'only-of-type':   function(m) {
        var p = Selector.xpath.pseudos; return p['first-of-type'](m) + p['last-of-type'](m);
      },
      nth: function(fragment, m) {
        var mm, formula = m[6], predicate;
        if (formula == 'even') formula = '2n+0';
        if (formula == 'odd')  formula = '2n+1';
        if (mm = formula.match(/^(\d+)$/)) // digit only
          return '[' + fragment + "= " + mm[1] + ']';
        if (mm = formula.match(/^(-?\d*)?n(([+-])(\d+))?/)) { // an+b
          if (mm[1] == "-") mm[1] = -1;
          var a = mm[1] ? Number(mm[1]) : 1;
          var b = mm[2] ? Number(mm[2]) : 0;
          predicate = "[((#{fragment} - #{b}) mod #{a} = 0) and " +
          "((#{fragment} - #{b}) div #{a} >= 0)]";
          return new Template(predicate).evaluate({
            fragment: fragment, a: a, b: b });
        }
      }
    }
  },

  criteria: {
    tagName:      'n = h.tagName(n, r, "#{1}", c);      c = false;',
    className:    'n = h.className(n, r, "#{1}", c);    c = false;',
    id:           'n = h.id(n, r, "#{1}", c);           c = false;',
    attrPresence: 'n = h.attrPresence(n, r, "#{1}", c); c = false;',
    attr: function(m) {
      m[3] = (m[5] || m[6]);
      return new Template('n = h.attr(n, r, "#{1}", "#{3}", "#{2}", c); c = false;').evaluate(m);
    },
    pseudo: function(m) {
      if (m[6]) m[6] = m[6].replace(/"/g, '\\"');
      return new Template('n = h.pseudo(n, "#{1}", "#{6}", r, c); c = false;').evaluate(m);
    },
    descendant:   'c = "descendant";',
    child:        'c = "child";',
    adjacent:     'c = "adjacent";',
    laterSibling: 'c = "laterSibling";'
  },

  patterns: {
    // combinators must be listed first
    // (and descendant needs to be last combinator)
    laterSibling: /^\s*~\s*/,
    child:        /^\s*>\s*/,
    adjacent:     /^\s*\+\s*/,
    descendant:   /^\s/,

    // selectors follow
    tagName:      /^\s*(\*|[\w\-]+)(\b|$)?/,
    id:           /^#([\w\-\*]+)(\b|$)/,
    className:    /^\.([\w\-\*]+)(\b|$)/,
    pseudo:
/^:((first|last|nth|nth-last|only)(-child|-of-type)|empty|checked|(en|dis)abled|not)(\((.*?)\))?(\b|$|(?=\s|[:+~>]))/,
    attrPresence: /^\[([\w]+)\]/,
    attr:         /\[((?:[\w-]*:)?[\w-]+)\s*(?:([!^$*~|]?=)\s*((['"])([^\4]*?)\4|([^'"][^\]]*?)))?\]/
  },

  // for Selector.match and Element#match
  assertions: {
    tagName: function(element, matches) {
      return matches[1].toUpperCase() == element.tagName.toUpperCase();
    },

    className: function(element, matches) {
      return Element.hasClassName(element, matches[1]);
    },

    id: function(element, matches) {
      return element.id === matches[1];
    },

    attrPresence: function(element, matches) {
      return Element.hasAttribute(element, matches[1]);
    },

    attr: function(element, matches) {
      var nodeValue = Element.readAttribute(element, matches[1]);
      return nodeValue && Selector.operators[matches[2]](nodeValue, matches[5] || matches[6]);
    }
  },

  handlers: {
    // UTILITY FUNCTIONS
    // joins two collections
    concat: function(a, b) {
      for (var i = 0, node; node = b[i]; i++)
        a.push(node);
      return a;
    },

    // marks an array of nodes for counting
    mark: function(nodes) {
      var _true = Prototype.emptyFunction;
      for (var i = 0, node; node = nodes[i]; i++)
        node._countedByPrototype = _true;
      return nodes;
    },

    unmark: function(nodes) {
      for (var i = 0, node; node = nodes[i]; i++)
        node._countedByPrototype = undefined;
      return nodes;
    },

    // mark each child node with its position (for nth calls)
    // "ofType" flag indicates whether we're indexing for nth-of-type
    // rather than nth-child
    index: function(parentNode, reverse, ofType) {
      parentNode._countedByPrototype = Prototype.emptyFunction;
      if (reverse) {
        for (var nodes = parentNode.childNodes, i = nodes.length - 1, j = 1; i >= 0; i--) {
          var node = nodes[i];
          if (node.nodeType == 1 && (!ofType || node._countedByPrototype)) node.nodeIndex = j++;
        }
      } else {
        for (var i = 0, j = 1, nodes = parentNode.childNodes; node = nodes[i]; i++)
          if (node.nodeType == 1 && (!ofType || node._countedByPrototype)) node.nodeIndex = j++;
      }
    },

    // filters out duplicates and extends all nodes
    unique: function(nodes) {
      if (nodes.length == 0) return nodes;
      var results = [], n;
      for (var i = 0, l = nodes.length; i < l; i++)
        if (!(n = nodes[i])._countedByPrototype) {
          n._countedByPrototype = Prototype.emptyFunction;
          results.push(Element.extend(n));
        }
      return Selector.handlers.unmark(results);
    },

    // COMBINATOR FUNCTIONS
    descendant: function(nodes) {
      var h = Selector.handlers;
      for (var i = 0, results = [], node; node = nodes[i]; i++)
        h.concat(results, node.getElementsByTagName('*'));
      return results;
    },

    child: function(nodes) {
      var h = Selector.handlers;
      for (var i = 0, results = [], node; node = nodes[i]; i++) {
        for (var j = 0, child; child = node.childNodes[j]; j++)
          if (child.nodeType == 1 && child.tagName != '!') results.push(child);
      }
      return results;
    },

    adjacent: function(nodes) {
      for (var i = 0, results = [], node; node = nodes[i]; i++) {
        var next = this.nextElementSibling(node);
        if (next) results.push(next);
      }
      return results;
    },

    laterSibling: function(nodes) {
      var h = Selector.handlers;
      for (var i = 0, results = [], node; node = nodes[i]; i++)
        h.concat(results, Element.nextSiblings(node));
      return results;
    },

    nextElementSibling: function(node) {
      while (node = node.nextSibling)
	      if (node.nodeType == 1) return node;
      return null;
    },

    previousElementSibling: function(node) {
      while (node = node.previousSibling)
        if (node.nodeType == 1) return node;
      return null;
    },

    // TOKEN FUNCTIONS
    tagName: function(nodes, root, tagName, combinator) {
      var uTagName = tagName.toUpperCase();
      var results = [], h = Selector.handlers;
      if (nodes) {
        if (combinator) {
          // fastlane for ordinary descendant combinators
          if (combinator == "descendant") {
            for (var i = 0, node; node = nodes[i]; i++)
              h.concat(results, node.getElementsByTagName(tagName));
            return results;
          } else nodes = this[combinator](nodes);
          if (tagName == "*") return nodes;
        }
        for (var i = 0, node; node = nodes[i]; i++)
          if (node.tagName.toUpperCase() === uTagName) results.push(node);
        return results;
      } else return root.getElementsByTagName(tagName);
    },

    id: function(nodes, root, id, combinator) {
      var targetNode = $(id), h = Selector.handlers;
      if (!targetNode) return [];
      if (!nodes && root == document) return [targetNode];
      if (nodes) {
        if (combinator) {
          if (combinator == 'child') {
            for (var i = 0, node; node = nodes[i]; i++)
              if (targetNode.parentNode == node) return [targetNode];
          } else if (combinator == 'descendant') {
            for (var i = 0, node; node = nodes[i]; i++)
              if (Element.descendantOf(targetNode, node)) return [targetNode];
          } else if (combinator == 'adjacent') {
            for (var i = 0, node; node = nodes[i]; i++)
              if (Selector.handlers.previousElementSibling(targetNode) == node)
                return [targetNode];
          } else nodes = h[combinator](nodes);
        }
        for (var i = 0, node; node = nodes[i]; i++)
          if (node == targetNode) return [targetNode];
        return [];
      }
      return (targetNode && Element.descendantOf(targetNode, root)) ? [targetNode] : [];
    },

    className: function(nodes, root, className, combinator) {
      if (nodes && combinator) nodes = this[combinator](nodes);
      return Selector.handlers.byClassName(nodes, root, className);
    },

    byClassName: function(nodes, root, className) {
      if (!nodes) nodes = Selector.handlers.descendant([root]);
      var needle = ' ' + className + ' ';
      for (var i = 0, results = [], node, nodeClassName; node = nodes[i]; i++) {
        nodeClassName = node.className;
        if (nodeClassName.length == 0) continue;
        if (nodeClassName == className || (' ' + nodeClassName + ' ').include(needle))
          results.push(node);
      }
      return results;
    },

    attrPresence: function(nodes, root, attr, combinator) {
      if (!nodes) nodes = root.getElementsByTagName("*");
      if (nodes && combinator) nodes = this[combinator](nodes);
      var results = [];
      for (var i = 0, node; node = nodes[i]; i++)
        if (Element.hasAttribute(node, attr)) results.push(node);
      return results;
    },

    attr: function(nodes, root, attr, value, operator, combinator) {
      if (!nodes) nodes = root.getElementsByTagName("*");
      if (nodes && combinator) nodes = this[combinator](nodes);
      var handler = Selector.operators[operator], results = [];
      for (var i = 0, node; node = nodes[i]; i++) {
        var nodeValue = Element.readAttribute(node, attr);
        if (nodeValue === null) continue;
        if (handler(nodeValue, value)) results.push(node);
      }
      return results;
    },

    pseudo: function(nodes, name, value, root, combinator) {
      if (nodes && combinator) nodes = this[combinator](nodes);
      if (!nodes) nodes = root.getElementsByTagName("*");
      return Selector.pseudos[name](nodes, value, root);
    }
  },

  pseudos: {
    'first-child': function(nodes, value, root) {
      for (var i = 0, results = [], node; node = nodes[i]; i++) {
        if (Selector.handlers.previousElementSibling(node)) continue;
          results.push(node);
      }
      return results;
    },
    'last-child': function(nodes, value, root) {
      for (var i = 0, results = [], node; node = nodes[i]; i++) {
        if (Selector.handlers.nextElementSibling(node)) continue;
          results.push(node);
      }
      return results;
    },
    'only-child': function(nodes, value, root) {
      var h = Selector.handlers;
      for (var i = 0, results = [], node; node = nodes[i]; i++)
        if (!h.previousElementSibling(node) && !h.nextElementSibling(node))
          results.push(node);
      return results;
    },
    'nth-child':        function(nodes, formula, root) {
      return Selector.pseudos.nth(nodes, formula, root);
    },
    'nth-last-child':   function(nodes, formula, root) {
      return Selector.pseudos.nth(nodes, formula, root, true);
    },
    'nth-of-type':      function(nodes, formula, root) {
      return Selector.pseudos.nth(nodes, formula, root, false, true);
    },
    'nth-last-of-type': function(nodes, formula, root) {
      return Selector.pseudos.nth(nodes, formula, root, true, true);
    },
    'first-of-type':    function(nodes, formula, root) {
      return Selector.pseudos.nth(nodes, "1", root, false, true);
    },
    'last-of-type':     function(nodes, formula, root) {
      return Selector.pseudos.nth(nodes, "1", root, true, true);
    },
    'only-of-type':     function(nodes, formula, root) {
      var p = Selector.pseudos;
      return p['last-of-type'](p['first-of-type'](nodes, formula, root), formula, root);
    },

    // handles the an+b logic
    getIndices: function(a, b, total) {
      if (a == 0) return b > 0 ? [b] : [];
      return $R(1, total).inject([], function(memo, i) {
        if (0 == (i - b) % a && (i - b) / a >= 0) memo.push(i);
        return memo;
      });
    },

    // handles nth(-last)-child, nth(-last)-of-type, and (first|last)-of-type
    nth: function(nodes, formula, root, reverse, ofType) {
      if (nodes.length == 0) return [];
      if (formula == 'even') formula = '2n+0';
      if (formula == 'odd')  formula = '2n+1';
      var h = Selector.handlers, results = [], indexed = [], m;
      h.mark(nodes);
      for (var i = 0, node; node = nodes[i]; i++) {
        if (!node.parentNode._countedByPrototype) {
          h.index(node.parentNode, reverse, ofType);
          indexed.push(node.parentNode);
        }
      }
      if (formula.match(/^\d+$/)) { // just a number
        formula = Number(formula);
        for (var i = 0, node; node = nodes[i]; i++)
          if (node.nodeIndex == formula) results.push(node);
      } else if (m = formula.match(/^(-?\d*)?n(([+-])(\d+))?/)) { // an+b
        if (m[1] == "-") m[1] = -1;
        var a = m[1] ? Number(m[1]) : 1;
        var b = m[2] ? Number(m[2]) : 0;
        var indices = Selector.pseudos.getIndices(a, b, nodes.length);
        for (var i = 0, node, l = indices.length; node = nodes[i]; i++) {
          for (var j = 0; j < l; j++)
            if (node.nodeIndex == indices[j]) results.push(node);
        }
      }
      h.unmark(nodes);
      h.unmark(indexed);
      return results;
    },

    'empty': function(nodes, value, root) {
      for (var i = 0, results = [], node; node = nodes[i]; i++) {
        // IE treats comments as element nodes
        if (node.tagName == '!' || (node.firstChild && !node.innerHTML.match(/^\s*$/))) continue;
        results.push(node);
      }
      return results;
    },

    'not': function(nodes, selector, root) {
      var h = Selector.handlers, selectorType, m;
      var exclusions = new Selector(selector).findElements(root);
      h.mark(exclusions);
      for (var i = 0, results = [], node; node = nodes[i]; i++)
        if (!node._countedByPrototype) results.push(node);
      h.unmark(exclusions);
      return results;
    },

    'enabled': function(nodes, value, root) {
      for (var i = 0, results = [], node; node = nodes[i]; i++)
        if (!node.disabled) results.push(node);
      return results;
    },

    'disabled': function(nodes, value, root) {
      for (var i = 0, results = [], node; node = nodes[i]; i++)
        if (node.disabled) results.push(node);
      return results;
    },

    'checked': function(nodes, value, root) {
      for (var i = 0, results = [], node; node = nodes[i]; i++)
        if (node.checked) results.push(node);
      return results;
    }
  },

  operators: {
    '=':  function(nv, v) { return nv == v; },
    '!=': function(nv, v) { return nv != v; },
    '^=': function(nv, v) { return nv.startsWith(v); },
    '$=': function(nv, v) { return nv.endsWith(v); },
    '*=': function(nv, v) { return nv.include(v); },
    '~=': function(nv, v) { return (' ' + nv + ' ').include(' ' + v + ' '); },
    '|=': function(nv, v) { return ('-' + nv.toUpperCase() + '-').include('-' + v.toUpperCase() + '-'); }
  },

  split: function(expression) {
    var expressions = [];
    expression.scan(/(([\w#:.~>+()\s-]+|\*|\[.*?\])+)\s*(,|$)/, function(m) {
      expressions.push(m[1].strip());
    });
    return expressions;
  },

  matchElements: function(elements, expression) {
    var matches = $$(expression), h = Selector.handlers;
    h.mark(matches);
    for (var i = 0, results = [], element; element = elements[i]; i++)
      if (element._countedByPrototype) results.push(element);
    h.unmark(matches);
    return results;
  },

  findElement: function(elements, expression, index) {
    if (Object.isNumber(expression)) {
      index = expression; expression = false;
    }
    return Selector.matchElements(elements, expression || '*')[index || 0];
  },

  findChildElements: function(element, expressions) {
    expressions = Selector.split(expressions.join(','));
    var results = [], h = Selector.handlers;
    for (var i = 0, l = expressions.length, selector; i < l; i++) {
      selector = new Selector(expressions[i].strip());
      h.concat(results, selector.findElements(element));
    }
    return (l > 1) ? h.unique(results) : results;
  }
});

if (Prototype.Browser.IE) {
  Object.extend(Selector.handlers, {
    // IE returns comment nodes on getElementsByTagName("*").
    // Filter them out.
    concat: function(a, b) {
      for (var i = 0, node; node = b[i]; i++)
        if (node.tagName !== "!") a.push(node);
      return a;
    },

    // IE improperly serializes _countedByPrototype in (inner|outer)HTML.
    unmark: function(nodes) {
      for (var i = 0, node; node = nodes[i]; i++)
        node.removeAttribute('_countedByPrototype');
      return nodes;
    }
  });
}

function $$() {
  return Selector.findChildElements(document, $A(arguments));
}
var Form = {
  reset: function(form) {
    $(form).reset();
    return form;
  },

  serializeElements: function(elements, options) {
    if (typeof options != 'object') options = { hash: !!options };
    else if (Object.isUndefined(options.hash)) options.hash = true;
    var key, value, submitted = false, submit = options.submit;

    var data = elements.inject({ }, function(result, element) {
      if (!element.disabled && element.name) {
        key = element.name; value = $(element).getValue();
        if (value != null && (element.type != 'submit' || (!submitted &&
            submit !== false && (!submit || key == submit) && (submitted = true)))) {
          if (key in result) {
            // a key is already present; construct an array of values
            if (!Object.isArray(result[key])) result[key] = [result[key]];
            result[key].push(value);
          }
          else result[key] = value;
        }
      }
      return result;
    });

    return options.hash ? data : Object.toQueryString(data);
  }
};

Form.Methods = {
  serialize: function(form, options) {
    return Form.serializeElements(Form.getElements(form), options);
  },

  getElements: function(form) {
    return $A($(form).getElementsByTagName('*')).inject([],
      function(elements, child) {
        if (Form.Element.Serializers[child.tagName.toLowerCase()])
          elements.push(Element.extend(child));
        return elements;
      }
    );
  },

  getInputs: function(form, typeName, name) {
    form = $(form);
    var inputs = form.getElementsByTagName('input');

    if (!typeName && !name) return $A(inputs).map(Element.extend);

    for (var i = 0, matchingInputs = [], length = inputs.length; i < length; i++) {
      var input = inputs[i];
      if ((typeName && input.type != typeName) || (name && input.name != name))
        continue;
      matchingInputs.push(Element.extend(input));
    }

    return matchingInputs;
  },

  disable: function(form) {
    form = $(form);
    Form.getElements(form).invoke('disable');
    return form;
  },

  enable: function(form) {
    form = $(form);
    Form.getElements(form).invoke('enable');
    return form;
  },

  findFirstElement: function(form) {
    var elements = $(form).getElements().findAll(function(element) {
      return 'hidden' != element.type && !element.disabled;
    });
    var firstByIndex = elements.findAll(function(element) {
      return element.hasAttribute('tabIndex') && element.tabIndex >= 0;
    }).sortBy(function(element) { return element.tabIndex }).first();

    return firstByIndex ? firstByIndex : elements.find(function(element) {
      return ['input', 'select', 'textarea'].include(element.tagName.toLowerCase());
    });
  },

  focusFirstElement: function(form) {
    form = $(form);
    form.findFirstElement().activate();
    return form;
  },

  request: function(form, options) {
    form = $(form), options = Object.clone(options || { });

    var params = options.parameters, action = form.readAttribute('action') || '';
    if (action.blank()) action = window.location.href;
    options.parameters = form.serialize(true);

    if (params) {
      if (Object.isString(params)) params = params.toQueryParams();
      Object.extend(options.parameters, params);
    }

    if (form.hasAttribute('method') && !options.method)
      options.method = form.method;

    return new Ajax.Request(action, options);
  }
};

/*--------------------------------------------------------------------------*/

Form.Element = {
  focus: function(element) {
    $(element).focus();
    return element;
  },

  select: function(element) {
    $(element).select();
    return element;
  }
};

Form.Element.Methods = {
  serialize: function(element) {
    element = $(element);
    if (!element.disabled && element.name) {
      var value = element.getValue();
      if (value != undefined) {
        var pair = { };
        pair[element.name] = value;
        return Object.toQueryString(pair);
      }
    }
    return '';
  },

  getValue: function(element) {
    element = $(element);
    var method = element.tagName.toLowerCase();
    return Form.Element.Serializers[method](element);
  },

  setValue: function(element, value) {
    element = $(element);
    var method = element.tagName.toLowerCase();
    Form.Element.Serializers[method](element, value);
    return element;
  },

  clear: function(element) {
    $(element).value = '';
    return element;
  },

  present: function(element) {
    return $(element).value != '';
  },

  activate: function(element) {
    element = $(element);
    try {
      element.focus();
      if (element.select && (element.tagName.toLowerCase() != 'input' ||
          !['button', 'reset', 'submit'].include(element.type)))
        element.select();
    } catch (e) { }
    return element;
  },

  disable: function(element) {
    element = $(element);
    element.blur();
    element.disabled = true;
    return element;
  },

  enable: function(element) {
    element = $(element);
    element.disabled = false;
    return element;
  }
};

/*--------------------------------------------------------------------------*/

var Field = Form.Element;
var $F = Form.Element.Methods.getValue;

/*--------------------------------------------------------------------------*/

Form.Element.Serializers = {
  input: function(element, value) {
    switch (element.type.toLowerCase()) {
      case 'checkbox':
      case 'radio':
        return Form.Element.Serializers.inputSelector(element, value);
      default:
        return Form.Element.Serializers.textarea(element, value);
    }
  },

  inputSelector: function(element, value) {
    if (Object.isUndefined(value)) return element.checked ? element.value : null;
    else element.checked = !!value;
  },

  textarea: function(element, value) {
    if (Object.isUndefined(value)) return element.value;
    else element.value = value;
  },

  select: function(element, index) {
    if (Object.isUndefined(index))
      return this[element.type == 'select-one' ?
        'selectOne' : 'selectMany'](element);
    else {
      var opt, value, single = !Object.isArray(index);
      for (var i = 0, length = element.length; i < length; i++) {
        opt = element.options[i];
        value = this.optionValue(opt);
        if (single) {
          if (value == index) {
            opt.selected = true;
            return;
          }
        }
        else opt.selected = index.include(value);
      }
    }
  },

  selectOne: function(element) {
    var index = element.selectedIndex;
    return index >= 0 ? this.optionValue(element.options[index]) : null;
  },

  selectMany: function(element) {
    var values, length = element.length;
    if (!length) return null;

    for (var i = 0, values = []; i < length; i++) {
      var opt = element.options[i];
      if (opt.selected) values.push(this.optionValue(opt));
    }
    return values;
  },

  optionValue: function(opt) {
    // extend element because hasAttribute may not be native
    return Element.extend(opt).hasAttribute('value') ? opt.value : opt.text;
  }
};

/*--------------------------------------------------------------------------*/

Abstract.TimedObserver = Class.create(PeriodicalExecuter, {
  initialize: function($super, element, frequency, callback) {
    $super(callback, frequency);
    this.element   = $(element);
    this.lastValue = this.getValue();
  },

  execute: function() {
    var value = this.getValue();
    if (Object.isString(this.lastValue) && Object.isString(value) ?
        this.lastValue != value : String(this.lastValue) != String(value)) {
      this.callback(this.element, value);
      this.lastValue = value;
    }
  }
});

Form.Element.Observer = Class.create(Abstract.TimedObserver, {
  getValue: function() {
    return Form.Element.getValue(this.element);
  }
});

Form.Observer = Class.create(Abstract.TimedObserver, {
  getValue: function() {
    return Form.serialize(this.element);
  }
});

/*--------------------------------------------------------------------------*/

Abstract.EventObserver = Class.create({
  initialize: function(element, callback) {
    this.element  = $(element);
    this.callback = callback;

    this.lastValue = this.getValue();
    if (this.element.tagName.toLowerCase() == 'form')
      this.registerFormCallbacks();
    else
      this.registerCallback(this.element);
  },

  onElementEvent: function() {
    var value = this.getValue();
    if (this.lastValue != value) {
      this.callback(this.element, value);
      this.lastValue = value;
    }
  },

  registerFormCallbacks: function() {
    Form.getElements(this.element).each(this.registerCallback, this);
  },

  registerCallback: function(element) {
    if (element.type) {
      switch (element.type.toLowerCase()) {
        case 'checkbox':
        case 'radio':
          Event.observe(element, 'click', this.onElementEvent.bind(this));
          break;
        default:
          Event.observe(element, 'change', this.onElementEvent.bind(this));
          break;
      }
    }
  }
});

Form.Element.EventObserver = Class.create(Abstract.EventObserver, {
  getValue: function() {
    return Form.Element.getValue(this.element);
  }
});

Form.EventObserver = Class.create(Abstract.EventObserver, {
  getValue: function() {
    return Form.serialize(this.element);
  }
});
if (!window.Event) var Event = { };

Object.extend(Event, {
  
  /**
  * Code for the Backspace key. Constant.
  * @memberOf {Event}
  */
  KEY_BACKSPACE: 8,
  
  /**
  * Code for the Tab key. Constant.
  * @memberOf {Event}
  */
  KEY_TAB:       9,
  
  /**
  * Code for the Return key. Constant.
  * @memberOf {Event}
  */
  KEY_RETURN:   13,
  
  /**
  * Code for the Esc key. Constant.
  * @memberOf {Event}
  */
  KEY_ESC:      27,
  
  /**
  * Code for the Left arrow key. Constant.
  * @memberOf {Event}
  */
  KEY_LEFT:     37,
  
  /**
  * Code for the Up arrow key. Constant.
  * @memberOf {Event}
  */
  KEY_UP:       38,
  
  /**
  * Code for the Right arrow key. Constant.
  * @memberOf {Event}
  */
  KEY_RIGHT:    39,
  
  /**
  * Code for the Down arrow key. Constant.
  * @memberOf {Event}
  */
  KEY_DOWN:     40,
  
  /**
  * Code for the Delete key. Constant.
  * @memberOf {Event}
  */
  KEY_DELETE:   46,
  
  /**
   * Code for the Home key. Constant.
   * @memberOf {Event}
   */
  KEY_HOME:     36,
  
   /**
   * Code for the End key. Constant.
   * @memberOf {Event}
   */
  KEY_END:      35,
  
  /**
   * Code for the Page Up key. Constant.
   * @memberOf {Event}
   */
  KEY_PAGEUP:   33,
  
   /**
   * Code for the Page Down key. Constant.
   * @memberOf {Event}
   */
  KEY_PAGEDOWN: 34,
  
  /**
   * Code for the Insert key. Constant.
   * @memberOf {Event}
   */
  KEY_INSERT:   45,

  cache: { },

  relatedTarget: function(event) {
    var element;
    switch(event.type) {
      case 'mouseover': element = event.fromElement; break;
      case 'mouseout':  element = event.toElement;   break;
      default: return null;
    }
    return Element.extend(element);
  }
});

Event.Methods = (function() {
  var isButton;

  if (Prototype.Browser.IE) {
    var buttonMap = { 0: 1, 1: 4, 2: 2 };
    isButton = function(event, code) {
      return event.button == buttonMap[code];
    };

  } else if (Prototype.Browser.WebKit) {
    isButton = function(event, code) {
      switch (code) {
        case 0: return event.which == 1 && !event.metaKey;
        case 1: return event.which == 1 && event.metaKey;
        default: return false;
      }
    };

  } else {
    isButton = function(event, code) {
      return event.which ? (event.which === code + 1) : (event.button === code);
    };
  }

  return {
    isLeftClick:   function(event) { return isButton(event, 0) },
    isMiddleClick: function(event) { return isButton(event, 1) },
    isRightClick:  function(event) { return isButton(event, 2) },

    element: function(event) {
      var node = Event.extend(event).target;
      return Element.extend(node.nodeType == Node.TEXT_NODE ? node.parentNode : node);
    },

    findElement: function(event, expression) {
      var element = Event.element(event);
      if (!expression) return element;
      var elements = [element].concat(element.ancestors());
      return Selector.findElement(elements, expression, 0);
    },

    pointer: function(event) {
      return {
        x: event.pageX || (event.clientX +
          (document.documentElement.scrollLeft || document.body.scrollLeft)),
        y: event.pageY || (event.clientY +
          (document.documentElement.scrollTop || document.body.scrollTop))
      };
    },

    pointerX: function(event) { return Event.pointer(event).x },
    pointerY: function(event) { return Event.pointer(event).y },

    stop: function(event) {
      Event.extend(event);
      event.preventDefault();
      event.stopPropagation();
      event.stopped = true;
    }
  };
})();

Event.extend = (function() {
  var methods = Object.keys(Event.Methods).inject({ }, function(m, name) {
    m[name] = Event.Methods[name].methodize();
    return m;
  });

  if (Prototype.Browser.IE) {
    Object.extend(methods, {
      stopPropagation: function() { this.cancelBubble = true },
      preventDefault:  function() { this.returnValue = false },
      inspect: function() { return "[object Event]" }
    });

    return function(event) {
      if (!event) return false;
      if (event._extendedByPrototype) return event;

      event._extendedByPrototype = Prototype.emptyFunction;
      var pointer = Event.pointer(event);
      Object.extend(event, {
        target: event.srcElement,
        relatedTarget: Event.relatedTarget(event),
        pageX:  pointer.x,
        pageY:  pointer.y
      });
      return Object.extend(event, methods);
    };

  } else {
    Event.prototype = Event.prototype || document.createEvent("HTMLEvents").__proto__;
    Object.extend(Event.prototype, methods);
    return Prototype.K;
  }
})();

Object.extend(Event, (function() {
  var cache = Event.cache;

  function getEventID(element) {
    if (element._prototypeEventID) return element._prototypeEventID[0];
    arguments.callee.id = arguments.callee.id || 1;
    return element._prototypeEventID = [++arguments.callee.id];
  }

  function getDOMEventName(eventName) {
    if (eventName && eventName.include(':')) return "dataavailable";
    return eventName;
  }

  function getCacheForID(id) {
    return cache[id] = cache[id] || { };
  }

  function getWrappersForEventName(id, eventName) {
    var c = getCacheForID(id);
    return c[eventName] = c[eventName] || [];
  }

  function createWrapper(element, eventName, handler) {
    var id = getEventID(element);
    var c = getWrappersForEventName(id, eventName);
    if (c.pluck("handler").include(handler)) return false;

    var wrapper = function(event) {
      if (!Event || !Event.extend ||
        (event.eventName && event.eventName != eventName))
          return false;

      Event.extend(event);
      handler.call(element, event);
    };

    wrapper.handler = handler;
    c.push(wrapper);
    return wrapper;
  }

  function findWrapper(id, eventName, handler) {
    var c = getWrappersForEventName(id, eventName);
    return c.find(function(wrapper) { return wrapper.handler == handler });
  }

  function destroyWrapper(id, eventName, handler) {
    var c = getCacheForID(id);
    if (!c[eventName]) return false;
    c[eventName] = c[eventName].without(findWrapper(id, eventName, handler));
  }

  function destroyCache() {
    for (var id in cache)
      for (var eventName in cache[id])
        cache[id][eventName] = null;
  }

  if (window.attachEvent) {
    window.attachEvent("onunload", destroyCache);
  }

  return {
    observe: function(element, eventName, handler) {
      element = $(element);
      var name = getDOMEventName(eventName);

      var wrapper = createWrapper(element, eventName, handler);
      if (!wrapper) return element;

      if (element.addEventListener) {
        element.addEventListener(name, wrapper, false);
      } else {
        element.attachEvent("on" + name, wrapper);
      }

      return element;
    },

    stopObserving: function(element, eventName, handler) {
      element = $(element);
      var id = getEventID(element), name = getDOMEventName(eventName);

      if (!handler && eventName) {
        getWrappersForEventName(id, eventName).each(function(wrapper) {
          element.stopObserving(eventName, wrapper.handler);
        });
        return element;

      } else if (!eventName) {
        Object.keys(getCacheForID(id)).each(function(eventName) {
          element.stopObserving(eventName);
        });
        return element;
      }

      var wrapper = findWrapper(id, eventName, handler);
      if (!wrapper) return element;

      if (element.removeEventListener) {
        element.removeEventListener(name, wrapper, false);
      } else {
        element.detachEvent("on" + name, wrapper);
      }

      destroyWrapper(id, eventName, handler);

      return element;
    },

    fire: function(element, eventName, memo) {
      element = $(element);
      if (element == document && document.createEvent && !element.dispatchEvent)
        element = document.documentElement;

      var event;
      if (document.createEvent) {
        event = document.createEvent("HTMLEvents");
        event.initEvent("dataavailable", true, true);
      } else {
        event = document.createEventObject();
        event.eventType = "ondataavailable";
      }

      event.eventName = eventName;
      event.memo = memo || { };

      if (document.createEvent) {
        element.dispatchEvent(event);
      } else {
        element.fireEvent(event.eventType, event);
      }

      return Event.extend(event);
    }
  };
})());

Object.extend(Event, Event.Methods);

Element.addMethods({
  fire:          Event.fire,
  observe:       Event.observe,
  stopObserving: Event.stopObserving
});

Object.extend(document, {
  fire:          Element.Methods.fire.methodize(),
  observe:       Element.Methods.observe.methodize(),
  stopObserving: Element.Methods.stopObserving.methodize(),
  loaded:        false
});

(function() {
  /* Support for the DOMContentLoaded event is based on work by Dan Webb,
     Matthias Miller, Dean Edwards and John Resig. */

  var timer;

  function fireContentLoadedEvent() {
    if (document.loaded) return;
    if (timer) window.clearInterval(timer);
    document.fire("dom:loaded");
    document.loaded = true;
  }

  if (document.addEventListener) {
    if (Prototype.Browser.WebKit) {
      timer = window.setInterval(function() {
        if (/loaded|complete/.test(document.readyState))
          fireContentLoadedEvent();
      }, 0);

      Event.observe(window, "load", fireContentLoadedEvent);

    } else {
      document.addEventListener("DOMContentLoaded",
        fireContentLoadedEvent, false);
    }

  } else {
    document.write("<script id=__onDOMContentLoaded defer src=//:><\/script>");
    $("__onDOMContentLoaded").onreadystatechange = function() {
      if (this.readyState == "complete") {
        this.onreadystatechange = null;
        fireContentLoadedEvent();
      }
    };
  }
})();
/*------------------------------- DEPRECATED -------------------------------*/

Hash.toQueryString = Object.toQueryString;

var Toggle = { display: Element.toggle };

Element.Methods.childOf = Element.Methods.descendantOf;

/**
 * @classDescription Inserts HTML before an element.
 * @constructor
 */

var Insertion = {
  Before: function(element, content) {
    return Element.insert(element, {before:content});
  },
  
  /**
   * Inserts HTML as the first child under an element.
   * @alias Insertion.Top
   * @param {Object} element
   * @param {Object} content
   */
  Top: function(element, content) {
    return Element.insert(element, {top:content});
  },

  /**
   * Inserts HTML as the last child under an element.
   * @alias Insertion.Bottom
   * @param {Object} element
   * @param {Object} content
   */
  Bottom: function(element, content) {
    return Element.insert(element, {bottom:content});
  },

  /**
   * Inserts HTML right after the closing tag of an element.
   * @alias Insertion.After
   * @param {Object} element
   * @param {Object} content
   */
  After: function(element, content) {
    return Element.insert(element, {after:content});
  }
};

var $continue = new Error('"throw $continue" is deprecated, use "return" instead');

// This should be moved to script.aculo.us; notice the deprecated methods
// further below, that map to the newer Element methods.
var Position = {
  // set to true if needed, warning: firefox performance problems
  // NOT neeeded for page scrolling, only if draggable contained in
  // scrollable elements
  includeScrollOffsets: false,

  // must be called before calling withinIncludingScrolloffset, every time the
  // page is scrolled
  prepare: function() {
    this.deltaX =  window.pageXOffset
                || document.documentElement.scrollLeft
                || document.body.scrollLeft
                || 0;
    this.deltaY =  window.pageYOffset
                || document.documentElement.scrollTop
                || document.body.scrollTop
                || 0;
  },

  // caches x/y coordinate pair to use with overlap
  within: function(element, x, y) {
    if (this.includeScrollOffsets)
      return this.withinIncludingScrolloffsets(element, x, y);
    this.xcomp = x;
    this.ycomp = y;
    this.offset = Element.cumulativeOffset(element);

    return (y >= this.offset[1] &&
            y <  this.offset[1] + element.offsetHeight &&
            x >= this.offset[0] &&
            x <  this.offset[0] + element.offsetWidth);
  },

  withinIncludingScrolloffsets: function(element, x, y) {
    var offsetcache = Element.cumulativeScrollOffset(element);

    this.xcomp = x + offsetcache[0] - this.deltaX;
    this.ycomp = y + offsetcache[1] - this.deltaY;
    this.offset = Element.cumulativeOffset(element);

    return (this.ycomp >= this.offset[1] &&
            this.ycomp <  this.offset[1] + element.offsetHeight &&
            this.xcomp >= this.offset[0] &&
            this.xcomp <  this.offset[0] + element.offsetWidth);
  },

  // within must be called directly before
  overlap: function(mode, element) {
    if (!mode) return 0;
    if (mode == 'vertical')
      return ((this.offset[1] + element.offsetHeight) - this.ycomp) /
        element.offsetHeight;
    if (mode == 'horizontal')
      return ((this.offset[0] + element.offsetWidth) - this.xcomp) /
        element.offsetWidth;
  },

  // Deprecation layer -- use newer Element methods now (1.5.2).

  cumulativeOffset: Element.Methods.cumulativeOffset,

  positionedOffset: Element.Methods.positionedOffset,

  absolutize: function(element) {
    Position.prepare();
    return Element.absolutize(element);
  },

  relativize: function(element) {
    Position.prepare();
    return Element.relativize(element);
  },

  realOffset: Element.Methods.cumulativeScrollOffset,

  offsetParent: Element.Methods.getOffsetParent,

  page: Element.Methods.viewportOffset,

  clone: function(source, target, options) {
    options = options || { };
    return Element.clonePosition(target, source, options);
  }
};

/*--------------------------------------------------------------------------*/

if (!document.getElementsByClassName) document.getElementsByClassName = function(instanceMethods){
  function iter(name) {
    return name.blank() ? null : "[contains(concat(' ', @class, ' '), ' " + name + " ')]";
  }

  instanceMethods.getElementsByClassName = Prototype.BrowserFeatures.XPath ?
  function(element, className) {
    className = className.toString().strip();
    var cond = /\s/.test(className) ? $w(className).map(iter).join('') : iter(className);
    return cond ? document._getElementsByXPath('.//*' + cond, element) : [];
  } : function(element, className) {
    className = className.toString().strip();
    var elements = [], classNames = (/\s/.test(className) ? $w(className) : null);
    if (!classNames && !className) return elements;

    var nodes = $(element).getElementsByTagName('*');
    className = ' ' + className + ' ';

    for (var i = 0, child, cn; child = nodes[i]; i++) {
      if (child.className && (cn = ' ' + child.className + ' ') && (cn.include(className) ||
          (classNames && classNames.all(function(name) {
            return !name.toString().blank() && cn.include(' ' + name + ' ');
          }))))
        elements.push(Element.extend(child));
    }
    return elements;
  };

  return function(className, parentElement) {
    return $(parentElement || document.body).getElementsByClassName(className);
  };
}(Element.Methods);

/*--------------------------------------------------------------------------*/

Element.ClassNames = Class.create();
Element.ClassNames.prototype = {
  initialize: function(element) {
    this.element = $(element);
  },

  _each: function(iterator) {
    this.element.className.split(/\s+/).select(function(name) {
      return name.length > 0;
    })._each(iterator);
  },

  set: function(className) {
    this.element.className = className;
  },

  add: function(classNameToAdd) {
    if (this.include(classNameToAdd)) return;
    this.set($A(this).concat(classNameToAdd).join(' '));
  },

  remove: function(classNameToRemove) {
    if (!this.include(classNameToRemove)) return;
    this.set($A(this).without(classNameToRemove).join(' '));
  },

  toString: function() {
    return $A(this).join(' ');
  }
};

Object.extend(Element.ClassNames.prototype, Enumerable);

/*--------------------------------------------------------------------------*/

Element.addMethods();