topical media & game development
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graphic-canvas-experiment-raytracer-script-prototype.js / js



  /*  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/
   *
  /*--------------------------------------------------------------------------*/
  
  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();
[] readme course(s) preface I 1 2 II 3 4 III 5 6 7 IV 8 9 10 V 11 12 afterthought(s) appendix reference(s) example(s) resource(s) _

(C) Æliens 20/2/2008

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