path: root/actionpack/lib/action_view/helpers/javascripts/prototype.js

/*  Prototype JavaScript framework, version 1.4.0_pre11
 *  (c) 2005 Sam Stephenson <sam@conio.net>
 *
 *  THIS FILE IS AUTOMATICALLY GENERATED. When sending patches, please diff
 *  against the source tree, available from the Prototype darcs repository. 
 *
 *  Prototype is freely distributable under the terms of an MIT-style license.
 *
 *  For details, see the Prototype web site: http://prototype.conio.net/
 *
/*--------------------------------------------------------------------------*/

var Prototype = {
  Version: '1.4.0_pre11',
  
  emptyFunction: function() {},
  K: function(x) {return x}
}

var Class = {
  create: function() {
    return function() { 
      this.initialize.apply(this, arguments);
    }
  }
}

var Abstract = new Object();

Object.extend = function(destination, source) {
  for (property in source) {
    destination[property] = source[property];
  }
  return destination;
}

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

Function.prototype.bind = function(object) {
  var __method = this;
  return function() {
    return __method.apply(object, arguments);
  }
}

Function.prototype.bindAsEventListener = function(object) {
  var __method = this;
  return function(event) {
    return __method.call(object, event || window.event);
  }
}

Object.extend(Number.prototype, {
  toColorPart: function() {
    var digits = this.toString(16);
    if (this < 16) return '0' + digits;
    return digits;
  },

  succ: function() {
    return this + 1;
  },
  
  times: function(iterator) {
    $R(0, this, true).each(iterator);
    return this;
  }
});

var Try = {
  these: function() {
    var returnValue;

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

    return returnValue;
  }
}

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

var PeriodicalExecuter = Class.create();
PeriodicalExecuter.prototype = {
  initialize: function(callback, frequency) {
    this.callback = callback;
    this.frequency = frequency;
    this.currentlyExecuting = false;

    this.registerCallback();
  },

  registerCallback: function() {
    setInterval(this.onTimerEvent.bind(this), this.frequency * 1000);
  },

  onTimerEvent: function() {
    if (!this.currentlyExecuting) {
      try { 
        this.currentlyExecuting = true;
        this.callback(); 
      } finally { 
        this.currentlyExecuting = false;
      }
    }
  }
}

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

function $() {
  var elements = new Array();

  for (var i = 0; i < arguments.length; i++) {
    var element = arguments[i];
    if (typeof element == 'string')
      element = document.getElementById(element);

    if (arguments.length == 1) 
      return element;

    elements.push(element);
  }

  return elements;
}

Object.extend(String.prototype, {
  stripTags: function() {
    return this.replace(/<\/?[^>]+>/gi, '');
  },

  escapeHTML: function() {
    var div = document.createElement('div');
    var text = document.createTextNode(this);
    div.appendChild(text);
    return div.innerHTML;
  },

  unescapeHTML: function() {
    var div = document.createElement('div');
    div.innerHTML = this.stripTags();
    return div.childNodes[0] ? div.childNodes[0].nodeValue : '';
  },
  
  toQueryParams: function() {
    var pairs = this.match(/^\??(.*)$/)[1].split('&');
    return pairs.inject({}, function(params, pairString) {
      var pair = pairString.split('=');
      params[pair[0]] = pair[1];
      return params;
    });
  },
  
  inspect: function() {
    return "'" + this.replace('\\', '\\\\').replace("'", '\\\'') + "'";
  }
});

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


var $break    = new Object();
var $continue = new Object();

var Enumerable = {
  each: function(iterator) {
    var index = 0;
    try {
      this._each(function(value) {
        try {
          iterator(value, index++);
        } catch (e) {
          if (e != $continue) throw e;
        }
      });
    } catch (e) {
      if (e != $break) throw e;
    }
  },
  
  all: function(iterator) {
    var result = true;
    this.each(function(value, index) {
      if (!(result &= (iterator || Prototype.K)(value, index))) 
        throw $break;
    });
    return result;
  },
  
  any: function(iterator) {
    var result = true;
    this.each(function(value, index) {
      if (result &= (iterator || Prototype.K)(value, index)) 
        throw $break;
    });
    return result;
  },
  
  collect: function(iterator) {
    var results = [];
    this.each(function(value, index) {
      results.push(iterator(value, index));
    });
    return results;
  },
  
  detect: function (iterator) {
    var result;
    this.each(function(value, index) {
      if (iterator(value, index)) {
        result = value;
        throw $break;
      }
    });
    return result;
  },
  
  findAll: function(iterator) {
    var results = [];
    this.each(function(value, index) {
      if (iterator(value, index))
        results.push(value);
    });
    return results;
  },
  
  grep: function(pattern, iterator) {
    var results = [];
    this.each(function(value, index) {
      var stringValue = value.toString();
      if (stringValue.match(pattern))
        results.push((iterator || Prototype.K)(value, index));
    })
    return results;
  },
  
  include: function(object) {
    var found = false;
    this.each(function(value) {
      if (value == object) {
        found = true;
        throw $break;
      }
    });
    return found;
  },
  
  inject: function(memo, iterator) {
    this.each(function(value, index) {
      memo = iterator(memo, value, index);
    });
    return memo;
  },
  
  invoke: function(method) {
    var args = $A(arguments).slice(1);
    return this.collect(function(value) {
      return value[method].apply(value, args);
    });
  },
  
  max: function(iterator) {
    var result;
    this.each(function(value, index) {
      value = (iterator || Prototype.K)(value, index);
      if (value >= (result || value))
        result = value;
    });
    return result;
  },
  
  min: function(iterator) {
    var result;
    this.each(function(value, index) {
      value = (iterator || Prototype.K)(value, index);
      if (value <= (result || value))
        result = value;
    });
    return result;
  },
  
  partition: function(iterator) {
    var trues = [], falses = [];
    this.each(function(value, index) {
      ((iterator || Prototype.K)(value, index) ? 
        trues : falses).push(value);
    });
    return [trues, falses];
  },
  
  pluck: function(property) {
    var results = [];
    this.each(function(value, index) {
      results.push(value[property]);
    });
    return results;
  },
  
  reject: function(iterator) {
    var results = [];
    this.each(function(value, index) {
      if (!iterator(value, index))
        results.push(value);
    });
    return results;
  },
  
  sortBy: function(iterator) {
    return this.collect(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');
  },
  
  toArray: function() {
    return this.collect(Prototype.K);
  },
  
  zip: function() {
    var iterator = Prototype.K, args = $A(arguments);
    if (typeof args.last() == 'function')
      iterator = args.pop();

    var collections = [this].concat(args).map($A);
    return this.map(function(value, index) {
      iterator(value = collections.pluck(index));
      return value;
    });
  },
  
  inspect: function() {
    return '#<Enumerable:' + this.toArray().inspect() + '>';
  }
}

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

var $A = Array.from = function(iterable) {
  if (iterable.toArray) {
    return iterable.toArray();
  } else {
    var results = [];
    for (var i = 0; i < iterable.length; i++)
      results.push(iterable[i]);
    return results;
  }
}

Object.extend(Array.prototype, Enumerable);

Object.extend(Array.prototype, {
  _each: function(iterator) {
    for (var i = 0; i < this.length; i++)
      iterator(this[i]);
  },
  
  first: function() {
    return this[0];
  },
  
  last: function() {
    return this[this.length - 1];
  },
  
  compact: function() {
    return this.select(function(value) {
      return value != undefined || value != null;
    });
  },
  
  flatten: function() {
    return this.inject([], function(array, value) {
      return array.concat(value.constructor == Array ?
        value.flatten() : [value]);
    });
  },
  
  without: function() {
    var values = $A(arguments);
    return this.select(function(value) {
      return !values.include(value);
    });
  },
  
  inspect: function() {
    return '[' + this.map(Object.inspect).join(', ') + ']';
  }
});

var Hash = {
  _each: function(iterator) {
    for (key in this) {
      var value = this[key];
      if (typeof value == 'function') continue;
      
      var pair = [key, value];
      pair.key = key;
      pair.value = value;
      iterator(pair);
    }
  },
  
  keys: function() {
    return this.pluck('key');
  },
  
  values: function() {
    return this.pluck('value');
  },
  
  merge: function(hash) {
    return $H(hash).inject($H(this), function(mergedHash, pair) {
      mergedHash[pair.key] = pair.value;
      return mergedHash;
    });
  },
  
  toQueryString: function() {
    return this.map(function(pair) {
      return pair.map(encodeURIComponent).join('=');
    }).join('&');
  },
  
  inspect: function() {
    return '#<Hash:{' + this.map(function(pair) {
      return pair.map(Object.inspect).join(': ');
    }).join(', ') + '}>';
  }
}

function $H(object) {
  var hash = Object.extend({}, object || {});
  Object.extend(hash, Enumerable);
  Object.extend(hash, Hash);
  return hash;
}

var Range = Class.create();
Object.extend(Range.prototype, Enumerable);
Object.extend(Range.prototype, {
  initialize: function(start, end, exclusive) {
    this.start = start;
    this.end = end;
    this.exclusive = exclusive;
  },
  
  _each: function(iterator) {
    var value = this.start;
    do {
      iterator(value);
      value = value.succ();
    } while (this.include(value));
  },
  
  include: function(value) {
    if (value < this.start) 
      return false;
    if (this.exclusive)
      return value < this.end;
    return value <= this.end;
  }
});

var $R = function(start, end, exclusive) {
  return new Range(start, end, exclusive);
}

var Ajax = {
  getTransport: function() {
    return Try.these(
      function() {return new ActiveXObject('Msxml2.XMLHTTP')},
      function() {return new ActiveXObject('Microsoft.XMLHTTP')},
      function() {return new XMLHttpRequest()}
    ) || false;
  },
  
  activeRequestCount: 0
}

Ajax.Responders = {
  responders: [],
  
  _each: function(iterator) {
    this.responders._each(iterator);
  },

  register: function(responderToAdd) {
    if (!this.include(responderToAdd))
      this.responders.push(responderToAdd);
  },
  
  unregister: function(responderToRemove) {
    this.responders = this.responders.without(responderToRemove);
  },
  
  dispatch: function(callback, request, transport, json) {
    this.each(function(responder) {
      if (responder[callback] && typeof responder[callback] == 'function') {
        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--;
  }
});

Ajax.Base = function() {};
Ajax.Base.prototype = {
  setOptions: function(options) {
    this.options = {
      method:       'post',
      asynchronous: true,
      parameters:   ''
    }
    Object.extend(this.options, options || {});
  },

  responseIsSuccess: function() {
    return this.transport.status == undefined
        || this.transport.status == 0 
        || (this.transport.status >= 200 && this.transport.status < 300);
  },

  responseIsFailure: function() {
    return !this.responseIsSuccess();
  }
}

Ajax.Request = Class.create();
Ajax.Request.Events = 
  ['Uninitialized', 'Loading', 'Loaded', 'Interactive', 'Complete'];

Ajax.Request.prototype = Object.extend(new Ajax.Base(), {
  initialize: function(url, options) {
    this.transport = Ajax.getTransport();
    this.setOptions(options);
    this.request(url);
  },

  request: function(url) {
    var parameters = this.options.parameters || '';
    if (parameters.length > 0) parameters += '&_=';

    try {
      this.url = url;
      if (this.options.method == 'get') 
        this.url += '?' + parameters;
      
      Ajax.Responders.dispatch('onCreate', this, this.transport);
      
      this.transport.open(this.options.method, this.url, 
        this.options.asynchronous);

      if (this.options.asynchronous) {
        this.transport.onreadystatechange = this.onStateChange.bind(this);
        setTimeout((function() {this.respondToReadyState(1)}).bind(this), 10);
      }

      this.setRequestHeaders();

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

    } catch (e) {
    }
  },

  setRequestHeaders: function() {
    var requestHeaders = 
      ['X-Requested-With', 'XMLHttpRequest',
       'X-Prototype-Version', Prototype.Version];

    if (this.options.method == 'post') {
      requestHeaders.push('Content-type', 
        'application/x-www-form-urlencoded');

      /* Force "Connection: close" for Mozilla browsers to work around
       * a bug where XMLHttpReqeuest sends an incorrect Content-length
       * header. See Mozilla Bugzilla #246651. 
       */
      if (this.transport.overrideMimeType)
        requestHeaders.push('Connection', 'close');
    }

    if (this.options.requestHeaders)
      requestHeaders.push.apply(requestHeaders, this.options.requestHeaders);

    for (var i = 0; i < requestHeaders.length; i += 2)
      this.transport.setRequestHeader(requestHeaders[i], requestHeaders[i+1]);
  },

  onStateChange: function() {
    var readyState = this.transport.readyState;
    if (readyState != 1)
      this.respondToReadyState(this.transport.readyState);
  },
  
  evalJSON: function() {
    try {
      var json = this.transport.getResponseHeader('X-JSON'), object;
      object = eval(json);
      return object;
    } catch (e) {
    }
  },

  respondToReadyState: function(readyState) {
    var event = Ajax.Request.Events[readyState];
    var transport = this.transport, json = this.evalJSON();

    if (event == 'Complete')
      (this.options['on' + this.transport.status]
       || this.options['on' + (this.responseIsSuccess() ? 'Success' : 'Failure')]
       || Prototype.emptyFunction)(transport, json);

    (this.options['on' + event] || Prototype.emptyFunction)(transport, json);
    Ajax.Responders.dispatch('on' + event, this, transport, json);

    /* Avoid memory leak in MSIE: clean up the oncomplete event handler */
    if (event == 'Complete')
      this.transport.onreadystatechange = Prototype.emptyFunction;
  }
});

Ajax.Updater = Class.create();
Ajax.Updater.ScriptFragment = '(?:<script.*?>)((\n|.)*?)(?:<\/script>)';

Object.extend(Object.extend(Ajax.Updater.prototype, Ajax.Request.prototype), {
  initialize: function(container, url, options) {
    this.containers = {
      success: container.success ? $(container.success) : $(container),
      failure: container.failure ? $(container.failure) :
        (container.success ? null : $(container))
    }

    this.transport = Ajax.getTransport();
    this.setOptions(options);

    var onComplete = this.options.onComplete || Prototype.emptyFunction;
    this.options.onComplete = (function(transport, object) {
      this.updateContent();
      onComplete(transport, object);
    }).bind(this);

    this.request(url);
  },

  updateContent: function() {
    var receiver = this.responseIsSuccess() ?
      this.containers.success : this.containers.failure;

    var match    = new RegExp(Ajax.Updater.ScriptFragment, 'img');
    var response = this.transport.responseText.replace(match, '');
    var scripts  = this.transport.responseText.match(match);

    if (receiver) {
      if (this.options.insertion) {
        new this.options.insertion(receiver, response);
      } else {
        receiver.innerHTML = response;
      }
    }

    if (this.responseIsSuccess()) {
      if (this.onComplete)
        setTimeout(this.onComplete.bind(this), 10);
    }

    if (this.options.evalScripts && scripts) {
      match = new RegExp(Ajax.Updater.ScriptFragment, 'im');
      setTimeout((function() {
        for (var i = 0; i < scripts.length; i++)
          eval(scripts[i].match(match)[1]);
      }).bind(this), 10);
    }
  }
});

Ajax.PeriodicalUpdater = Class.create();
Ajax.PeriodicalUpdater.prototype = Object.extend(new Ajax.Base(), {
  initialize: function(container, url, options) {
    this.setOptions(options);
    this.onComplete = this.options.onComplete;

    this.frequency = (this.options.frequency || 2);
    this.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.onComplete = undefined;
    clearTimeout(this.timer);
    (this.onComplete || Ajax.emptyFunction).apply(this, arguments);
  },

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

      this.lastText = request.responseText;
    }
    this.timer = setTimeout(this.onTimerEvent.bind(this), 
      this.decay * this.frequency * 1000);
  },

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

document.getElementsByClassName = function(className, parentElement) {
  var children = (document.body || $(parentElement)).getElementsByTagName('*');
  return $A(children).inject([], function(elements, child) {
    if (Element.hasClassName(child, className))
      elements.push(child);
    return elements;
  });
}

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

if (!window.Element) {
  var Element = new Object();
}

Object.extend(Element, {
  visible: function(element) {
    return $(element).style.display != 'none';
  },
  
  toggle: function() {
    for (var i = 0; i < arguments.length; i++) {
      var element = $(arguments[i]);
      Element[Element.visible(element) ? 'hide' : 'show'](element);
    }
  },

  hide: function() {
    for (var i = 0; i < arguments.length; i++) {
      var element = $(arguments[i]);
      element.style.display = 'none';
    }
  },
  
  show: function() {
    for (var i = 0; i < arguments.length; i++) {
      var element = $(arguments[i]);
      element.style.display = '';
    }
  },

  remove: function(element) {
    element = $(element);
    element.parentNode.removeChild(element);
  },
  
  getHeight: function(element) {
    element = $(element);
    return element.offsetHeight; 
  },
  
  classNames: function(element) {
    return new Element.ClassNames(element);
  },

  hasClassName: function(element, className) {
    if (!(element = $(element))) return;
    return Element.classNames(element).include(className);
  },

  addClassName: function(element, className) {
    if (!(element = $(element))) return;
    return Element.classNames(element).add(className);
  },

  removeClassName: function(element, className) {
    if (!(element = $(element))) return;
    return Element.classNames(element).remove(className);
  },
  
  // removes whitespace-only text node children
  cleanWhitespace: function(element) {
    element = $(element);
    for (var i = 0; i < element.childNodes.length; i++) {
      var node = element.childNodes[i];
      if (node.nodeType == 3 && !/\S/.test(node.nodeValue)) 
        Element.remove(node);
    }
  },
  
  empty: function(element) {
    return $(element).innerHTML.match(/^\s*$/);
  },
  
  scrollTo: function(element) {
    element = $(element);
    var x = element.x ? element.x : element.offsetLeft,
        y = element.y ? element.y : element.offsetTop;
    window.scrollTo(x, y);
  }
});

var Toggle = new Object();
Toggle.display = Element.toggle;

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

Abstract.Insertion = function(adjacency) {
  this.adjacency = adjacency;
}

Abstract.Insertion.prototype = {
  initialize: function(element, content) {
    this.element = $(element);
    this.content = content;
    
    if (this.adjacency && this.element.insertAdjacentHTML) {
      try {
        this.element.insertAdjacentHTML(this.adjacency, this.content);
      } catch (e) {
        if (this.element.tagName.toLowerCase() == 'tbody') {
          this.fragment = this.contentFromAnonymousTable();
          this.insertContent();
        } else {
          throw e;
        }
      }
    } else {
      this.range = this.element.ownerDocument.createRange();
      if (this.initializeRange) this.initializeRange();
      this.fragment = this.range.createContextualFragment(this.content);
      this.insertContent();
    }
  },
  
  contentFromAnonymousTable: function() {
    var div = document.createElement('div');
    div.innerHTML = '<table><tbody>' + this.content + '</tbody></table>';
    return div.childNodes[0].childNodes[0].childNodes[0];
  }
}

var Insertion = new Object();

Insertion.Before = Class.create();
Insertion.Before.prototype = Object.extend(new Abstract.Insertion('beforeBegin'), {
  initializeRange: function() {
    this.range.setStartBefore(this.element);
  },
  
  insertContent: function() {
    this.element.parentNode.insertBefore(this.fragment, this.element);
  }
});

Insertion.Top = Class.create();
Insertion.Top.prototype = Object.extend(new Abstract.Insertion('afterBegin'), {
  initializeRange: function() {
    this.range.selectNodeContents(this.element);
    this.range.collapse(true);
  },
  
  insertContent: function() {  
    this.element.insertBefore(this.fragment, this.element.firstChild);
  }
});

Insertion.Bottom = Class.create();
Insertion.Bottom.prototype = Object.extend(new Abstract.Insertion('beforeEnd'), {
  initializeRange: function() {
    this.range.selectNodeContents(this.element);
    this.range.collapse(this.element);
  },
  
  insertContent: function() {
    this.element.appendChild(this.fragment);
  }
});

Insertion.After = Class.create();
Insertion.After.prototype = Object.extend(new Abstract.Insertion('afterEnd'), {
  initializeRange: function() {
    this.range.setStartAfter(this.element);
  },
  
  insertContent: function() {
    this.element.parentNode.insertBefore(this.fragment, 
      this.element.nextSibling);
  }
});

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

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(this.toArray().concat(classNameToAdd).join(' '));
  },
  
  remove: function(classNameToRemove) {
    if (!this.include(classNameToRemove)) return;
    this.set(this.select(function(className) {
      return className != classNameToRemove;
    }));
  },
  
  toString: function() {
    return this.toArray().join(' ');
  }
}

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

var Field = {
  clear: function() {
    for (var i = 0; i < arguments.length; i++)
      $(arguments[i]).value = '';
  },

  focus: function(element) {
    $(element).focus();
  },
  
  present: function() {
    for (var i = 0; i < arguments.length; i++)
      if ($(arguments[i]).value == '') return false;
    return true;
  },
  
  select: function(element) {
    $(element).select();
  },
   
  activate: function(element) {
    $(element).focus();
    $(element).select();
  }
}

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

var Form = {
  serialize: function(form) {
    var elements = Form.getElements($(form));
    var queryComponents = new Array();
    
    for (var i = 0; i < elements.length; i++) {
      var queryComponent = Form.Element.serialize(elements[i]);
      if (queryComponent)
        queryComponents.push(queryComponent);
    }
    
    return queryComponents.join('&');
  },
  
  getElements: function(form) {
    var form = $(form);
    var elements = new Array();

    for (tagName in Form.Element.Serializers) {
      var tagElements = form.getElementsByTagName(tagName);
      for (var j = 0; j < tagElements.length; j++)
        elements.push(tagElements[j]);
    }
    return elements;
  },
  
  getInputs: function(form, typeName, name) {
    var form = $(form);
    var inputs = form.getElementsByTagName('input');
    
    if (!typeName && !name)
      return inputs;
      
    var matchingInputs = new Array();
    for (var i = 0; i < inputs.length; i++) {
      var input = inputs[i];
      if ((typeName && input.type != typeName) ||
          (name && input.name != name)) 
        continue;
      matchingInputs.push(input);
    }

    return matchingInputs;
  },

  disable: function(form) {
    var elements = Form.getElements(form);
    for (var i = 0; i < elements.length; i++) {
      var element = elements[i];
      element.blur();
      element.disabled = 'true';
    }
  },

  enable: function(form) {
    var elements = Form.getElements(form);
    for (var i = 0; i < elements.length; i++) {
      var element = elements[i];
      element.disabled = '';
    }
  },

  focusFirstElement: function(form) {
    var form = $(form);
    var elements = Form.getElements(form);
    for (var i = 0; i < elements.length; i++) {
      var element = elements[i];
      if (element.type != 'hidden' && !element.disabled) {
        Field.activate(element);
        break;
      }
    }
  },

  reset: function(form) {
    $(form).reset();
  }
}

Form.Element = {
  serialize: function(element) {
    var element = $(element);
    var method = element.tagName.toLowerCase();
    var parameter = Form.Element.Serializers[method](element);
    
    if (parameter)
      return encodeURIComponent(parameter[0]) + '=' + 
        encodeURIComponent(parameter[1]);                   
  },
  
  getValue: function(element) {
    var element = $(element);
    var method = element.tagName.toLowerCase();
    var parameter = Form.Element.Serializers[method](element);
    
    if (parameter) 
      return parameter[1];
  }
}

Form.Element.Serializers = {
  input: function(element) {
    switch (element.type.toLowerCase()) {
      case 'submit':
      case 'hidden':
      case 'password':
      case 'text':
        return Form.Element.Serializers.textarea(element);
      case 'checkbox':  
      case 'radio':
        return Form.Element.Serializers.inputSelector(element);
    }
    return false;
  },

  inputSelector: function(element) {
    if (element.checked)
      return [element.name, element.value];
  },

  textarea: function(element) {
    return [element.name, element.value];
  },
  
  select: function(element) {
    return Form.Element.Serializers[element.type == 'select-one' ? 
      'selectOne' : 'selectMany'](element);
  },
  
  selectOne: function(element) {
    var value = '', opt, index = element.selectedIndex;
    if (index >= 0) {
      opt = element.options[index];
      value = opt.value;
      if (!value && !('value' in opt))
        value = opt.text;
    }
    return [element.name, value];
  },
  
  selectMany: function(element) {
    var value = new Array();
    for (var i = 0; i < element.length; i++) {
      var opt = element.options[i];
      if (opt.selected) {
        var optValue = opt.value;
        if (!optValue && !('value' in opt))
          optValue = opt.text;
        value.push(optValue);
      }
    }
    return [element.name, value];
  }
}

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

var $F = Form.Element.getValue;

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

Abstract.TimedObserver = function() {}
Abstract.TimedObserver.prototype = {
  initialize: function(element, frequency, callback) {
    this.frequency = frequency;
    this.element   = $(element);
    this.callback  = callback;
    
    this.lastValue = this.getValue();
    this.registerCallback();
  },
  
  registerCallback: function() {
    setInterval(this.onTimerEvent.bind(this), this.frequency * 1000);
  },
  
  onTimerEvent: function() {
    var value = this.getValue();
    if (this.lastValue != value) {
      this.callback(this.element, value);
      this.lastValue = value;
    }
  }
}

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

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

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

Abstract.EventObserver = function() {}
Abstract.EventObserver.prototype = {
  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() {
    var elements = Form.getElements(this.element);
    for (var i = 0; i < elements.length; i++)
      this.registerCallback(elements[i]);
  },
  
  registerCallback: function(element) {
    if (element.type) {
      switch (element.type.toLowerCase()) {
        case 'checkbox':  
        case 'radio':
          element.target = this;
          element.prev_onclick = element.onclick || Prototype.emptyFunction;
          element.onclick = function() {
            this.prev_onclick(); 
            this.target.onElementEvent();
          }
          break;
        case 'password':
        case 'text':
        case 'textarea':
        case 'select-one':
        case 'select-multiple':
          element.target = this;
          element.prev_onchange = element.onchange || Prototype.emptyFunction;
          element.onchange = function() {
            this.prev_onchange(); 
            this.target.onElementEvent();
          }
          break;
      }
    }    
  }
}

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

Form.EventObserver = Class.create();
Form.EventObserver.prototype = Object.extend(new Abstract.EventObserver(), {
  getValue: function() {
    return Form.serialize(this.element);
  }
});


if (!window.Event) {
  var Event = new Object();
}

Object.extend(Event, {
  KEY_BACKSPACE: 8,
  KEY_TAB:       9,
  KEY_RETURN:   13,
  KEY_ESC:      27,
  KEY_LEFT:     37,
  KEY_UP:       38,
  KEY_RIGHT:    39,
  KEY_DOWN:     40,
  KEY_DELETE:   46,

  element: function(event) {
    return event.target || event.srcElement;
  },

  isLeftClick: function(event) {
    return (((event.which) && (event.which == 1)) ||
            ((event.button) && (event.button == 1)));
  },

  pointerX: function(event) {
    return event.pageX || (event.clientX + 
      (document.documentElement.scrollLeft || document.body.scrollLeft));
  },

  pointerY: function(event) {
    return event.pageY || (event.clientY + 
      (document.documentElement.scrollTop || document.body.scrollTop));
  },

  stop: function(event) {
    if (event.preventDefault) { 
      event.preventDefault(); 
      event.stopPropagation(); 
    } else {
      event.returnValue = false;
      event.cancelBubble = true;
    }
  },

  // find the first node with the given tagName, starting from the
  // node the event was triggered on; traverses the DOM upwards
  findElement: function(event, tagName) {
    var element = Event.element(event);
    while (element.parentNode && (!element.tagName ||
        (element.tagName.toUpperCase() != tagName.toUpperCase())))
      element = element.parentNode;
    return element;
  },

  observers: false,
  
  _observeAndCache: function(element, name, observer, useCapture) {
    if (!this.observers) this.observers = [];
    if (element.addEventListener) {
      this.observers.push([element, name, observer, useCapture]);
      element.addEventListener(name, observer, useCapture);
    } else if (element.attachEvent) {
      this.observers.push([element, name, observer, useCapture]);
      element.attachEvent('on' + name, observer);
    }
  },
  
  unloadCache: function() {
    if (!Event.observers) return;
    for (var i = 0; i < Event.observers.length; i++) {
      Event.stopObserving.apply(this, Event.observers[i]);
      Event.observers[i][0] = null;
    }
    Event.observers = false;
  },

  observe: function(element, name, observer, useCapture) {
    var element = $(element);
    useCapture = useCapture || false;
    
    if (name == 'keypress' &&
        (navigator.appVersion.match(/Konqueror|Safari|KHTML/)
        || element.attachEvent))
      name = 'keydown';
    
    this._observeAndCache(element, name, observer, useCapture);
  },

  stopObserving: function(element, name, observer, useCapture) {
    var element = $(element);
    useCapture = useCapture || false;
    
    if (name == 'keypress' &&
        (navigator.appVersion.match(/Konqueror|Safari|KHTML/)
        || element.detachEvent))
      name = 'keydown';
    
    if (element.removeEventListener) {
      element.removeEventListener(name, observer, useCapture);
    } else if (element.detachEvent) {
      element.detachEvent('on' + name, observer);
    }
  }
});

/* prevent memory leaks in IE */
Event.observe(window, 'unload', Event.unloadCache, false);

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;
  },

  realOffset: function(element) {
    var valueT = 0, valueL = 0;
    do {
      valueT += element.scrollTop  || 0;
      valueL += element.scrollLeft || 0; 
      element = element.parentNode;
    } while (element);
    return [valueL, valueT];
  },

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

  // 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 = this.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 = this.realOffset(element);

    this.xcomp = x + offsetcache[0] - this.deltaX;
    this.ycomp = y + offsetcache[1] - this.deltaY;
    this.offset = this.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;
  },

  clone: function(source, target) {
    source = $(source);
    target = $(target);
    target.style.position = 'absolute';
    var offsets = this.cumulativeOffset(source);
    target.style.top    = offsets[1] + 'px';
    target.style.left   = offsets[0] + 'px';
    target.style.width  = source.offsetWidth + 'px';
    target.style.height = source.offsetHeight + 'px';
  }
}