/*  Prototype JavaScript framework, version 1.5.0
 *  (c) 2005-2007 Sam Stephenson
 *
 *  Prototype is freely distributable under the terms of an MIT-style license.
 *  For details, see the Prototype web site: http://prototype.conio.net/
 *
/*--------------------------------------------------------------------------*/

if (typeof(PROTOTYPE_JS) == 'undefined') // 한번만 실행
{

	var PROTOTYPE_JS = true;

	var Prototype = {
	  Version: '1.5.0',
	  BrowserFeatures: {
		XPath: !!document.evaluate
	  },

	  ScriptFragment: '(?:<script.*?>)((\n|\r|.)*?)(?:<\/script>)',
	  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 (var property in source) {
		destination[property] = source[property];
	  }
	  return destination;
	}

	Object.extend(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;
		}
	  },

	  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);
	  }
	});

	Function.prototype.bind = function() {
	  var __method = this, args = $A(arguments), object = args.shift();
	  return function() {
		return __method.apply(object, args.concat($A(arguments)));
	  }
	}

	Function.prototype.bindAsEventListener = function(object) {
	  var __method = this, args = $A(arguments), object = args.shift();
	  return function(event) {
		return __method.apply(object, [( event || window.event)].concat(args).concat($A(arguments)));
	  }
	}

	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, length = arguments.length; i < 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() {
		this.timer = setInterval(this.onTimerEvent.bind(this), this.frequency * 1000);
	  },

	  stop: function() {
		if (!this.timer) return;
		clearInterval(this.timer);
		this.timer = null;
	  },

	  onTimerEvent: function() {
		if (!this.currentlyExecuting) {
		  try {
			this.currentlyExecuting = true;
			this.callback(this);
		  } finally {
			this.currentlyExecuting = false;
		  }
		}
	  }
	}
	String.interpret = function(value){
	  return value == null ? '' : String(value);
	}

	Object.extend(String.prototype, {
	  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;
	  },

	  sub: function(pattern, replacement, count) {
		replacement = this.gsub.prepareReplacement(replacement);
		count = count === undefined ? 1 : count;

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

	  scan: function(pattern, iterator) {
		this.gsub(pattern, iterator);
		return this;
	  },

	  truncate: function(length, truncation) {
		length = length || 30;
		truncation = truncation === undefined ? '...' : truncation;
		return this.length > length ?
		  this.slice(0, length - truncation.length) + truncation : this;
	  },

	  strip: function() {
		return this.replace(/^\s+/, '').replace(/\s+$/, '');
	  },

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

	  stripScripts: function() {
		return this.replace(new RegExp(Prototype.ScriptFragment, 'img'), '');
	  },

	  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];
		});
	  },

	  evalScripts: function() {
		return this.extractScripts().map(function(script) { return eval(script) });
	  },

	  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.length > 1 ?
		  $A(div.childNodes).inject('',function(memo,node){ return memo+node.nodeValue }) :
		  div.childNodes[0].nodeValue) : '';
	  },

	  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 name = decodeURIComponent(pair[0]);
			var value = pair[1] ? decodeURIComponent(pair[1]) : undefined;

			if (hash[name] !== undefined) {
			  if (hash[name].constructor != Array)
				hash[name] = [hash[name]];
			  if (value) hash[name].push(value);
			}
			else hash[name] = value;
		  }
		  return hash;
		});
	  },

	  toArray: function() {
		return this.split('');
	  },

	  succ: function() {
		return this.slice(0, this.length - 1) +
		  String.fromCharCode(this.charCodeAt(this.length - 1) + 1);
	  },

	  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;
	  },

	  capitalize: function(){
		return this.charAt(0).toUpperCase() + this.substring(1).toLowerCase();
	  },

	  underscore: function() {
		return this.gsub(/::/, '/').gsub(/([A-Z]+)([A-Z][a-z])/,'#{1}_#{2}').gsub(/([a-z\d])([A-Z])/,'#{1}_#{2}').gsub(/-/,'_').toLowerCase();
	  },

	  dasherize: function() {
		return this.gsub(/_/,'-');
	  },

	  inspect: function(useDoubleQuotes) {
		var escapedString = this.replace(/\\/g, '\\\\');
		if (useDoubleQuotes)
		  return '"' + escapedString.replace(/"/g, '\\"') + '"';
		else
		  return "'" + escapedString.replace(/'/g, '\\\'') + "'";
	  }
	});

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

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

	var Template = Class.create();
	Template.Pattern = /(^|.|\r|\n)(#\{(.*?)\})/;
	Template.prototype = {
	  initialize: function(template, pattern) {
		this.template = template.toString();
		this.pattern  = pattern || Template.Pattern;
	  },

	  evaluate: function(object) {
		return this.template.gsub(this.pattern, function(match) {
		  var before = match[1];
		  if (before == '\\') return match[2];
		  return before + String.interpret(object[match[3]]);
		});
	  }
	}

	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;
		}
		return this;
	  },

	  eachSlice: function(number, iterator) {
		var index = -number, slices = [], array = this.toArray();
		while ((index += number) < array.length)
		  slices.push(array.slice(index, index+number));
		return slices.map(iterator);
	  },

	  all: function(iterator) {
		var result = true;
		this.each(function(value, index) {
		  result = result && !!(iterator || Prototype.K)(value, index);
		  if (!result) throw $break;
		});
		return result;
	  },

	  any: function(iterator) {
		var result = false;
		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 || Prototype.K)(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;
	  },

	  inGroupsOf: function(number, fillWith) {
		fillWith = fillWith === undefined ? null : fillWith;
		return this.eachSlice(number, function(slice) {
		  while(slice.length < number) slice.push(fillWith);
		  return slice;
		});
	  },

	  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.map(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 (result == undefined || value >= result)
			result = value;
		});
		return result;
	  },

	  min: function(iterator) {
		var result;
		this.each(function(value, index) {
		  value = (iterator || Prototype.K)(value, index);
		  if (result == undefined || value < result)
			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.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');
	  },

	  toArray: function() {
		return this.map();
	  },

	  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) {
		  return iterator(collections.pluck(index));
		});
	  },

	  size: function() {
		return this.toArray().length;
	  },

	  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) return [];
	  if (iterable.toArray) {
		return iterable.toArray();
	  } else {
		var results = [];
		for (var i = 0, length = iterable.length; i < length; i++)
		  results.push(iterable[i]);
		return results;
	  }
	}

	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]);
	  },

	  clear: function() {
		this.length = 0;
		return this;
	  },

	  first: function() {
		return this[0];
	  },

	  last: function() {
		return this[this.length - 1];
	  },

	  compact: function() {
		return this.select(function(value) {
		  return value != null;
		});
	  },

	  flatten: function() {
		return this.inject([], function(array, value) {
		  return array.concat(value && value.constructor == Array ?
			value.flatten() : [value]);
		});
	  },

	  without: function() {
		var values = $A(arguments);
		return this.select(function(value) {
		  return !values.include(value);
		});
	  },

	  indexOf: function(object) {
		for (var i = 0, length = this.length; i < length; i++)
		  if (this[i] == object) return i;
		return -1;
	  },

	  reverse: function(inline) {
		return (inline !== false ? this : this.toArray())._reverse();
	  },

	  reduce: function() {
		return this.length > 1 ? this : this[0];
	  },

	  uniq: function() {
		return this.inject([], function(array, value) {
		  return array.include(value) ? array : array.concat([value]);
		});
	  },

	  clone: function() {
		return [].concat(this);
	  },

	  size: function() {
		return this.length;
	  },

	  inspect: function() {
		return '[' + this.map(Object.inspect).join(', ') + ']';
	  }
	});

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

	function $w(string){
	  string = string.strip();
	  return string ? string.split(/\s+/) : [];
	}

	if(window.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(arguments[i].constructor == Array) {
			for(var j = 0, arrayLength = arguments[i].length; j < arrayLength; j++)
			  array.push(arguments[i][j]);
		  } else {
			array.push(arguments[i]);
		  }
		}
		return array;
	  }
	}
	var Hash = function(obj) {
	  Object.extend(this, obj || {});
	};

	Object.extend(Hash, {
	  toQueryString: function(obj) {
		var parts = [];

		  this.prototype._each.call(obj, function(pair) {
		  if (!pair.key) return;

		  if (pair.value && pair.value.constructor == Array) {
			var values = pair.value.compact();
			if (values.length < 2) pair.value = values.reduce();
			else {
				key = encodeURIComponent(pair.key);
			  values.each(function(value) {
				value = value != undefined ? encodeURIComponent(value) : '';
				parts.push(key + '=' + encodeURIComponent(value));
			  });
			  return;
			}
		  }
		  if (pair.value == undefined) pair[1] = '';
		  parts.push(pair.map(encodeURIComponent).join('='));
		  });

		return parts.join('&');
	  }
	});

	Object.extend(Hash.prototype, Enumerable);
	Object.extend(Hash.prototype, {
	  _each: function(iterator) {
		for (var key in this) {
		  var value = this[key];
		  if (value && value == Hash.prototype[key]) 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(this, function(mergedHash, pair) {
		  mergedHash[pair.key] = pair.value;
		  return mergedHash;
		});
	  },

	  remove: function() {
		var result;
		for(var i = 0, length = arguments.length; i < length; i++) {
		  var value = this[arguments[i]];
		  if (value !== undefined){
			if (result === undefined) result = value;
			else {
			  if (result.constructor != Array) result = [result];
			  result.push(value)
			}
		  }
		  delete this[arguments[i]];
		}
		return result;
	  },

	  toQueryString: function() {
		return Hash.toQueryString(this);
	  },

	  inspect: function() {
		return '#<Hash:{' + this.map(function(pair) {
		  return pair.map(Object.inspect).join(': ');
		}).join(', ') + '}>';
	  }
	});

	function $H(object) {
	  if (object && object.constructor == Hash) return object;
	  return new Hash(object);
	};
	ObjectRange = Class.create();
	Object.extend(ObjectRange.prototype, Enumerable);
	Object.extend(ObjectRange.prototype, {
	  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();
		}
	  },

	  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 ObjectRange(start, end, exclusive);
	}

	var Ajax = {
	  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 = {
	  responders: [],

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

	  register: function(responder) {
		if (!this.include(responder))
		  this.responders.push(responder);
	  },

	  unregister: function(responder) {
		this.responders = this.responders.without(responder);
	  },

	  dispatch: function(callback, request, transport, json) {
		this.each(function(responder) {
		  if (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,
		  contentType:  'application/x-www-form-urlencoded',
		  encoding:     'UTF-8',
		  parameters:   ''
		}
		Object.extend(this.options, options || {});

		this.options.method = this.options.method.toLowerCase();
		if (typeof this.options.parameters == 'string')
		  this.options.parameters = this.options.parameters.toQueryParams();
	  }
	}

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

	Ajax.Request.prototype = Object.extend(new Ajax.Base(), {
	  _complete: false,

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

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

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

		params = Hash.toQueryString(params);
		if (params && /Konqueror|Safari|KHTML/.test(navigator.userAgent)) params += '&_='

		// when GET, append parameters to URL
		if (this.method == 'get' && params)
		  this.url += (this.url.indexOf('?') > -1 ? '&' : '?') + params;

		try {
		  Ajax.Responders.dispatch('onCreate', this, this.transport);

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

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

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

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

		  this.transport.send(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 (typeof extras.push == 'function')
			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() {
		return !this.transport.status
			|| (this.transport.status >= 200 && this.transport.status < 300);
	  },

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

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

		  if ((this.getHeader('Content-type') || 'text/javascript').strip().
			match(/^(text|application)\/(x-)?(java|ecma)script(;.*)?$/i))
			  this.evalResponse();
		}

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

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

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

	  evalJSON: function() {
		try {
		  var json = this.getHeader('X-JSON');
		  return json ? eval('(' + json + ')') : null;
		} catch (e) { return null }
	  },

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

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

	Ajax.Updater = Class.create();

	Object.extend(Object.extend(Ajax.Updater.prototype, Ajax.Request.prototype), {
	  initialize: function(container, url, options) {
		this.container = {
		  success: (container.success || 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, param) {
		  this.updateContent();
		  onComplete(transport, param);
		}).bind(this);

		this.request(url);
	  },

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

		if (!this.options.evalScripts) response = response.stripScripts();

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

		if (this.success()) {
		  if (this.onComplete)
			setTimeout(this.onComplete.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 = (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(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);
	  }
	});
	function $(element) {
	  if (arguments.length > 1) {
		for (var i = 0, elements = [], length = arguments.length; i < length; i++)
		  elements.push($(arguments[i]));
		return elements;
	  }
	  if (typeof element == 'string')
		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(query.snapshotItem(i));
		return results;
	  };
	}

	document.getElementsByClassName = function(className, parentElement) {
	  if (Prototype.BrowserFeatures.XPath) {
		var q = ".//*[contains(concat(' ', @class, ' '), ' " + className + " ')]";
		return document._getElementsByXPath(q, parentElement);
	  } else {
		var children = ($(parentElement) || document.body).getElementsByTagName('*');
		var elements = [], child;
		for (var i = 0, length = children.length; i < length; i++) {
		  child = children[i];
		  if (Element.hasClassName(child, className))
			elements.push(Element.extend(child));
		}
		return elements;
	  }
	};

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

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

	Element.extend = function(element) {
	  if (!element || _nativeExtensions || element.nodeType == 3) return element;

	  if (!element._extended && element.tagName && element != window) {
		var methods = Object.clone(Element.Methods), cache = Element.extend.cache;

		if (element.tagName == 'FORM')
		  Object.extend(methods, Form.Methods);
		if (['INPUT', 'TEXTAREA', 'SELECT'].include(element.tagName))
		  Object.extend(methods, Form.Element.Methods);

		Object.extend(methods, Element.Methods.Simulated);

		for (var property in methods) {
		  var value = methods[property];
		  if (typeof value == 'function' && !(property in element))
			element[property] = cache.findOrStore(value);
		}
	  }

	  element._extended = true;
	  return element;
	};

	Element.extend.cache = {
	  findOrStore: function(value) {
		return this[value] = this[value] || function() {
		  return value.apply(null, [this].concat($A(arguments)));
		}
	  }
	};

	Element.Methods = {
	  visible: function(element) {
		return $(element).style.display != 'none';
	  },

	  toggle: function(element) {
		element = $(element);
		Element[Element.visible(element) ? 'hide' : 'show'](element);
		return element;
	  },

	  hide: function(element) {
		$(element).style.display = 'none';
		return element;
	  },

	  show: function(element) {
		$(element).style.display = '';
		return element;
	  },

	  remove: function(element) {
		element = $(element);
		element.parentNode.removeChild(element);
		return element;
	  },

	  update: function(element, html) {
		html = typeof html == 'undefined' ? '' : html.toString();
		$(element).innerHTML = html.stripScripts();
		setTimeout(function() {html.evalScripts()}, 10);
		return element;
	  },

	  replace: function(element, html) {
		element = $(element);
		html = typeof html == 'undefined' ? '' : html.toString();
		if (element.outerHTML) {
		  element.outerHTML = html.stripScripts();
		} else {
		  var range = element.ownerDocument.createRange();
		  range.selectNodeContents(element);
		  element.parentNode.replaceChild(
			range.createContextualFragment(html.stripScripts()), element);
		}
		setTimeout(function() {html.evalScripts()}, 10);
		return 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 + '>';
	  },

	  recursivelyCollect: function(element, property) {
		element = $(element);
		var elements = [];
		while (element = element[property])
		  if (element.nodeType == 1)
			elements.push(Element.extend(element));
		return elements;
	  },

	  ancestors: function(element) {
		return $(element).recursivelyCollect('parentNode');
	  },

	  descendants: function(element) {
		return $A($(element).getElementsByTagName('*'));
	  },

	  immediateDescendants: function(element) {
		if (!(element = $(element).firstChild)) return [];
		while (element && element.nodeType != 1) element = element.nextSibling;
		if (element) return [element].concat($(element).nextSiblings());
		return [];
	  },

	  previousSiblings: function(element) {
		return $(element).recursivelyCollect('previousSibling');
	  },

	  nextSiblings: function(element) {
		return $(element).recursivelyCollect('nextSibling');
	  },

	  siblings: function(element) {
		element = $(element);
		return element.previousSiblings().reverse().concat(element.nextSiblings());
	  },

	  match: function(element, selector) {
		if (typeof selector == 'string')
		  selector = new Selector(selector);
		return selector.match($(element));
	  },

	  up: function(element, expression, index) {
		return Selector.findElement($(element).ancestors(), expression, index);
	  },

	  down: function(element, expression, index) {
		return Selector.findElement($(element).descendants(), expression, index);
	  },

	  previous: function(element, expression, index) {
		return Selector.findElement($(element).previousSiblings(), expression, index);
	  },

	  next: function(element, expression, index) {
		return Selector.findElement($(element).nextSiblings(), expression, index);
	  },

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

	  getElementsByClassName: function(element, className) {
		return document.getElementsByClassName(className, element);
	  },

	  readAttribute: function(element, name) {
		element = $(element);
		if (document.all && !window.opera) {
		  var t = Element._attributeTranslations;
		  if (t.values[name]) return t.values[name](element, name);
		  if (t.names[name])  name = t.names[name];
		  var attribute = element.attributes[name];
		  if(attribute) return attribute.nodeValue;
		}
		return element.getAttribute(name);
	  },

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

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

	  classNames: function(element) {
		return new Element.ClassNames(element);
	  },

	  hasClassName: function(element, className) {
		if (!(element = $(element))) return;
		var elementClassName = element.className;
		if (elementClassName.length == 0) return false;
		if (elementClassName == className ||
			elementClassName.match(new RegExp("(^|\\s)" + className + "(\\s|$)")))
		  return true;
		return false;
	  },

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

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

	  toggleClassName: function(element, className) {
		if (!(element = $(element))) return;
		Element.classNames(element)[element.hasClassName(className) ? 'remove' : 'add'](className);
		return element;
	  },

	  observe: function() {
		Event.observe.apply(Event, arguments);
		return $A(arguments).first();
	  },

	  stopObserving: function() {
		Event.stopObserving.apply(Event, arguments);
		return $A(arguments).first();
	  },

	  // removes whitespace-only text node children
	  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;
	  },

	  empty: function(element) {
		return $(element).innerHTML.match(/^\s*$/);
	  },

	  descendantOf: function(element, ancestor) {
		element = $(element), ancestor = $(ancestor);
		while (element = element.parentNode)
		  if (element == ancestor) return true;
		return false;
	  },

	  scrollTo: function(element) {
		element = $(element);
		var pos = Position.cumulativeOffset(element);
		window.scrollTo(pos[0], pos[1]);
		return element;
	  },

	  getStyle: function(element, style) {
		element = $(element);
		if (['float','cssFloat'].include(style))
		  style = (typeof element.style.styleFloat != 'undefined' ? 'styleFloat' : 'cssFloat');
		style = style.camelize();
		var value = element.style[style];
		if (!value) {
		  if (document.defaultView && document.defaultView.getComputedStyle) {
			var css = document.defaultView.getComputedStyle(element, null);
			value = css ? css[style] : null;
		  } else if (element.currentStyle) {
			value = element.currentStyle[style];
		  }
		}

		if((value == 'auto') && ['width','height'].include(style) && (element.getStyle('display') != 'none'))
		  value = element['offset'+style.capitalize()] + 'px';

		if (window.opera && ['left', 'top', 'right', 'bottom'].include(style))
		  if (Element.getStyle(element, 'position') == 'static') value = 'auto';
		if(style == 'opacity') {
		  if(value) return parseFloat(value);
		  if(value = (element.getStyle('filter') || '').match(/alpha\(opacity=(.*)\)/))
			if(value[1]) return parseFloat(value[1]) / 100;
		  return 1.0;
		}
		return value == 'auto' ? null : value;
	  },

	  setStyle: function(element, style) {
		element = $(element);
		for (var name in style) {
		  var value = style[name];
		  if(name == 'opacity') {
			if (value == 1) {
			  value = (/Gecko/.test(navigator.userAgent) &&
				!/Konqueror|Safari|KHTML/.test(navigator.userAgent)) ? 0.999999 : 1.0;
			  if(/MSIE/.test(navigator.userAgent) && !window.opera)
				element.style.filter = element.getStyle('filter').replace(/alpha\([^\)]*\)/gi,'');
			} else if(value == '') {
			  if(/MSIE/.test(navigator.userAgent) && !window.opera)
				element.style.filter = element.getStyle('filter').replace(/alpha\([^\)]*\)/gi,'');
			} else {
			  if(value < 0.00001) value = 0;
			  if(/MSIE/.test(navigator.userAgent) && !window.opera)
				element.style.filter = element.getStyle('filter').replace(/alpha\([^\)]*\)/gi,'') +
				  'alpha(opacity='+value*100+')';
			}
		  } else if(['float','cssFloat'].include(name)) name = (typeof element.style.styleFloat != 'undefined') ? 'styleFloat' : 'cssFloat';
		  element.style[name.camelize()] = value;
		}
		return 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};
	  },

	  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;
	  },

	  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;
	  },

	  makeClipping: function(element) {
		element = $(element);
		if (element._overflow) return element;
		element._overflow = element.style.overflow || 'auto';
		if ((Element.getStyle(element, 'overflow') || 'visible') != 'hidden')
		  element.style.overflow = 'hidden';
		return element;
	  },

	  undoClipping: function(element) {
		element = $(element);
		if (!element._overflow) return element;
		element.style.overflow = element._overflow == 'auto' ? '' : element._overflow;
		element._overflow = null;
		return element;
	  }
	};

	Object.extend(Element.Methods, {childOf: Element.Methods.descendantOf});

	Element._attributeTranslations = {};

	Element._attributeTranslations.names = {
	  colspan:   "colSpan",
	  rowspan:   "rowSpan",
	  valign:    "vAlign",
	  datetime:  "dateTime",
	  accesskey: "accessKey",
	  tabindex:  "tabIndex",
	  enctype:   "encType",
	  maxlength: "maxLength",
	  readonly:  "readOnly",
	  longdesc:  "longDesc"
	};

	Element._attributeTranslations.values = {
	  _getAttr: function(element, attribute) {
		return element.getAttribute(attribute, 2);
	  },

	  _flag: function(element, attribute) {
		return $(element).hasAttribute(attribute) ? attribute : null;
	  },

	  style: function(element) {
		return element.style.cssText.toLowerCase();
	  },

	  title: function(element) {
		var node = element.getAttributeNode('title');
		return node.specified ? node.nodeValue : null;
	  }
	};

	Object.extend(Element._attributeTranslations.values, {
	  href: Element._attributeTranslations.values._getAttr,
	  src:  Element._attributeTranslations.values._getAttr,
	  disabled: Element._attributeTranslations.values._flag,
	  checked:  Element._attributeTranslations.values._flag,
	  readonly: Element._attributeTranslations.values._flag,
	  multiple: Element._attributeTranslations.values._flag
	});

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

	// IE is missing .innerHTML support for TABLE-related elements
	if (document.all && !window.opera){
	  Element.Methods.update = function(element, html) {
		element = $(element);
		html = typeof html == 'undefined' ? '' : html.toString();
		var tagName = element.tagName.toUpperCase();
		if (['THEAD','TBODY','TR','TD'].include(tagName)) {
		  var div = document.createElement('div');
		  switch (tagName) {
			case 'THEAD':
			case 'TBODY':
			  div.innerHTML = '<table><tbody>' +  html.stripScripts() + '</tbody></table>';
			  depth = 2;
			  break;
			case 'TR':
			  div.innerHTML = '<table><tbody><tr>' +  html.stripScripts() + '</tr></tbody></table>';
			  depth = 3;
			  break;
			case 'TD':
			  div.innerHTML = '<table><tbody><tr><td>' +  html.stripScripts() + '</td></tr></tbody></table>';
			  depth = 4;
		  }
		  $A(element.childNodes).each(function(node){
			element.removeChild(node)
		  });
		  depth.times(function(){ div = div.firstChild });

		  $A(div.childNodes).each(
			function(node){ element.appendChild(node) });
		} else {
		  element.innerHTML = html.stripScripts();
		}
		setTimeout(function() {html.evalScripts()}, 10);
		return element;
	  }
	};

	Object.extend(Element, Element.Methods);

	var _nativeExtensions = false;

	if(/Konqueror|Safari|KHTML/.test(navigator.userAgent))
	  ['', 'Form', 'Input', 'TextArea', 'Select'].each(function(tag) {
		var className = 'HTML' + tag + 'Element';
		if(window[className]) return;
		var klass = window[className] = {};
		klass.prototype = document.createElement(tag ? tag.toLowerCase() : 'div').__proto__;
	  });

	Element.addMethods = function(methods) {
	  Object.extend(Element.Methods, methods || {});

	  function copy(methods, destination, onlyIfAbsent) {
		onlyIfAbsent = onlyIfAbsent || false;
		var cache = Element.extend.cache;
		for (var property in methods) {
		  var value = methods[property];
		  if (!onlyIfAbsent || !(property in destination))
			destination[property] = cache.findOrStore(value);
		}
	  }

	  if (typeof HTMLElement != 'undefined') {
		copy(Element.Methods, HTMLElement.prototype);
		copy(Element.Methods.Simulated, HTMLElement.prototype, true);
		copy(Form.Methods, HTMLFormElement.prototype);
		[HTMLInputElement, HTMLTextAreaElement, HTMLSelectElement].each(function(klass) {
		  copy(Form.Element.Methods, klass.prototype);
		});
		_nativeExtensions = true;
	  }
	}

	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.stripScripts();

		if (this.adjacency && this.element.insertAdjacentHTML) {
		  try {
			this.element.insertAdjacentHTML(this.adjacency, this.content);
		  } catch (e) {
			var tagName = this.element.tagName.toUpperCase();
			if (['TBODY', 'TR'].include(tagName)) {
			  this.insertContent(this.contentFromAnonymousTable());
			} else {
			  throw e;
			}
		  }
		} else {
		  this.range = this.element.ownerDocument.createRange();
		  if (this.initializeRange) this.initializeRange();
		  this.insertContent([this.range.createContextualFragment(this.content)]);
		}

		setTimeout(function() {content.evalScripts()}, 10);
	  },

	  contentFromAnonymousTable: function() {
		var div = document.createElement('div');
		div.innerHTML = '<table><tbody>' + this.content + '</tbody></table>';
		return $A(div.childNodes[0].childNodes[0].childNodes);
	  }
	}

	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(fragments) {
		fragments.each((function(fragment) {
		  this.element.parentNode.insertBefore(fragment, this.element);
		}).bind(this));
	  }
	});

	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(fragments) {
		fragments.reverse(false).each((function(fragment) {
		  this.element.insertBefore(fragment, this.element.firstChild);
		}).bind(this));
	  }
	});

	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(fragments) {
		fragments.each((function(fragment) {
		  this.element.appendChild(fragment);
		}).bind(this));
	  }
	});

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

	  insertContent: function(fragments) {
		fragments.each((function(fragment) {
		  this.element.parentNode.insertBefore(fragment,
			this.element.nextSibling);
		}).bind(this));
	  }
	});

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

	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);
	var Selector = Class.create();
	Selector.prototype = {
	  initialize: function(expression) {
		this.params = {classNames: []};
		this.expression = expression.toString().strip();
		this.parseExpression();
		this.compileMatcher();
	  },

	  parseExpression: function() {
		function abort(message) { throw 'Parse error in selector: ' + message; }

		if (this.expression == '')  abort('empty expression');

		var params = this.params, expr = this.expression, match, modifier, clause, rest;
		while (match = expr.match(/^(.*)\[([a-z0-9_:-]+?)(?:([~\|!]?=)(?:"([^"]*)"|([^\]\s]*)))?\]$/i)) {
		  params.attributes = params.attributes || [];
		  params.attributes.push({name: match[2], operator: match[3], value: match[4] || match[5] || ''});
		  expr = match[1];
		}

		if (expr == '*') return this.params.wildcard = true;

		while (match = expr.match(/^([^a-z0-9_-])?([a-z0-9_-]+)(.*)/i)) {
		  modifier = match[1], clause = match[2], rest = match[3];
		  switch (modifier) {
			case '#':       params.id = clause; break;
			case '.':       params.classNames.push(clause); break;
			case '':
			case undefined: params.tagName = clause.toUpperCase(); break;
			default:        abort(expr.inspect());
		  }
		  expr = rest;
		}

		if (expr.length > 0) abort(expr.inspect());
	  },

	  buildMatchExpression: function() {
		var params = this.params, conditions = [], clause;

		if (params.wildcard)
		  conditions.push('true');
		if (clause = params.id)
		  conditions.push('element.readAttribute("id") == ' + clause.inspect());
		if (clause = params.tagName)
		  conditions.push('element.tagName.toUpperCase() == ' + clause.inspect());
		if ((clause = params.classNames).length > 0)
		  for (var i = 0, length = clause.length; i < length; i++)
			conditions.push('element.hasClassName(' + clause[i].inspect() + ')');
		if (clause = params.attributes) {
		  clause.each(function(attribute) {
			var value = 'element.readAttribute(' + attribute.name.inspect() + ')';
			var splitValueBy = function(delimiter) {
			  return value + ' && ' + value + '.split(' + delimiter.inspect() + ')';
			}

			switch (attribute.operator) {
			  case '=':       conditions.push(value + ' == ' + attribute.value.inspect()); break;
			  case '~=':      conditions.push(splitValueBy(' ') + '.include(' + attribute.value.inspect() + ')'); break;
			  case '|=':      conditions.push(
								splitValueBy('-') + '.first().toUpperCase() == ' + attribute.value.toUpperCase().inspect()
							  ); break;
			  case '!=':      conditions.push(value + ' != ' + attribute.value.inspect()); break;
			  case '':
			  case undefined: conditions.push('element.hasAttribute(' + attribute.name.inspect() + ')'); break;
			  default:        throw 'Unknown operator ' + attribute.operator + ' in selector';
			}
		  });
		}

		return conditions.join(' && ');
	  },

	  compileMatcher: function() {
		this.match = new Function('element', 'if (!element.tagName) return false; \
		  element = $(element); \
		  return ' + this.buildMatchExpression());
	  },

	  findElements: function(scope) {
		var element;

		if (element = $(this.params.id))
		  if (this.match(element))
			if (!scope || Element.childOf(element, scope))
			  return [element];

		scope = (scope || document).getElementsByTagName(this.params.tagName || '*');

		var results = [];
		for (var i = 0, length = scope.length; i < length; i++)
		  if (this.match(element = scope[i]))
			results.push(Element.extend(element));

		return results;
	  },

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

	Object.extend(Selector, {
	  matchElements: function(elements, expression) {
		var selector = new Selector(expression);
		return elements.select(selector.match.bind(selector)).map(Element.extend);
	  },

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

	  findChildElements: function(element, expressions) {
		return expressions.map(function(expression) {
		  return expression.match(/[^\s"]+(?:"[^"]*"[^\s"]+)*/g).inject([null], function(results, expr) {
			var selector = new Selector(expr);
			return results.inject([], function(elements, result) {
			  return elements.concat(selector.findElements(result || element));
			});
		  });
		}).flatten();
	  }
	});

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

	  serializeElements: function(elements, getHash) {
		var data = elements.inject({}, function(result, element) {
		  if (!element.disabled && element.name) {
			var key = element.name, value = $(element).getValue();
			if (value != undefined) {
			  if (result[key]) {
				if (result[key].constructor != Array) result[key] = [result[key]];
				result[key].push(value);
			  }
			  else result[key] = value;
			}
		  }
		  return result;
		});

		return getHash ? data : Hash.toQueryString(data);
	  }
	};

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

	  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().each(function(element) {
		  element.blur();
		  element.disabled = 'true';
		});
		return form;
	  },

	  enable: function(form) {
		form = $(form);
		form.getElements().each(function(element) {
		  element.disabled = '';
		});
		return form;
	  },

	  findFirstElement: function(form) {
		return $(form).getElements().find(function(element) {
		  return element.type != 'hidden' && !element.disabled &&
			['input', 'select', 'textarea'].include(element.tagName.toLowerCase());
		});
	  },

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

	Object.extend(Form, Form.Methods);

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

	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 Hash.toQueryString(pair);
		  }
		}
		return '';
	  },

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

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

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

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

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

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

	Object.extend(Form.Element, Form.Element.Methods);
	var Field = Form.Element;
	var $F = Form.Element.getValue;

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

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

	  inputSelector: function(element) {
		return element.checked ? element.value : null;
	  },

	  textarea: function(element) {
		return element.value;
	  },

	  select: function(element) {
		return this[element.type == 'select-one' ?
		  'selectOne' : 'selectMany'](element);
	  },

	  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 = 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();
		var changed = ('string' == typeof this.lastValue && 'string' == typeof value
		  ? this.lastValue != value : String(this.lastValue) != String(value));
		if (changed) {
		  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() {
		Form.getElements(this.element).each(this.registerCallback.bind(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();
	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,
	  KEY_HOME:     36,
	  KEY_END:      35,
	  KEY_PAGEUP:   33,
	  KEY_PAGEDOWN: 34,

	  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, length = Event.observers.length; i < length; i++) {
		  Event.stopObserving.apply(this, Event.observers[i]);
		  Event.observers[i][0] = null;
		}
		Event.observers = false;
	  },

	  observe: function(element, name, observer, useCapture) {
		element = $(element);
		useCapture = useCapture || false;

		if (name == 'keypress' &&
			(navigator.appVersion.match(/Konqueror|Safari|KHTML/)
			|| element.attachEvent))
		  name = 'keydown';

		Event._observeAndCache(element, name, observer, useCapture);
	  },

	  stopObserving: function(element, name, observer, useCapture) {
		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) {
		  try {
			element.detachEvent('on' + name, observer);
		  } catch (e) {}
		}
	  }
	});

	/* prevent memory leaks in IE */
	if (navigator.appVersion.match(/\bMSIE\b/))
	  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];
	  },

	  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 == 'relative' || p == 'absolute') break;
		  }
		} while (element);
		return [valueL, valueT];
	  },

	  offsetParent: 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;
	  },

	  // 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;
	  },

	  page: 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)
			if (Element.getStyle(element,'position')=='absolute') break;

		} while (element = element.offsetParent);

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

		return [valueL, valueT];
	  },

	  clone: function(source, target) {
		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 = Position.page(source);

		// find coordinate system to use
		target = $(target);
		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(target,'position') == 'absolute') {
		  parent = Position.offsetParent(target);
		  delta = Position.page(parent);
		}

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

	  absolutize: function(element) {
		element = $(element);
		if (element.style.position == 'absolute') return;
		Position.prepare();

		var offsets = Position.positionedOffset(element);
		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';
	  },

	  relativize: function(element) {
		element = $(element);
		if (element.style.position == 'relative') return;
		Position.prepare();

		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;
	  }
	}

	// Safari returns margins on body which is incorrect if the child is absolutely
	// positioned.  For performance reasons, redefine Position.cumulativeOffset for
	// KHTML/WebKit only.
	if (/Konqueror|Safari|KHTML/.test(navigator.userAgent)) {
	  Position.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 [valueL, valueT];
	  }
	}

	Element.addMethods();
}