var Engine = {
  detect: function() {
    var UA = navigator.userAgent;
    this.isKHTML = /Konqueror|Safari|KHTML/.test(UA);
    this.isGecko = (/Gecko/.test(UA) && !this.isKHTML);
    this.isOpera = /Opera/.test(UA);
    this.isMSIE  = (/MSIE/.test(UA) && !this.isOpera);
    this.isMSIE7 = this.isMSIE && !(/MSIE 6\./.test(UA) && !this.isOpera);
    this.isMSIE6 = this.isMSIE && !this.isMSIE7;
  }
}
Engine.detect();

var Builder = {
  NODEMAP: {
    AREA: 'map',
    CAPTION: 'table',
    COL: 'table',
    COLGROUP: 'table',
    LEGEND: 'fieldset',
    OPTGROUP: 'select',
    OPTION: 'select',
    PARAM: 'object',
    TBODY: 'table',
    TD: 'table',
    TFOOT: 'table',
    TH: 'table',
    THEAD: 'table',
    TR: 'table'
  },
  // note: For Firefox < 1.5, OPTION and OPTGROUP tags are currently broken,
  //       due to a Firefox bug
  node: function(elementName) {
    elementName = elementName.toUpperCase();
    
    // try innerHTML approach
    var parentTag = this.NODEMAP[elementName] || 'div';
    var parentElement = document.createElement(parentTag);
    try { // prevent IE "feature": http://dev.rubyonrails.org/ticket/2707
      parentElement.innerHTML = "<" + elementName + "></" + elementName + ">";
    } catch(e) {}
    var element = parentElement.firstChild || null;
      
    // see if browser added wrapping tags
    if(element && (element.tagName != elementName))
      element = element.getElementsByTagName(elementName)[0];
    
    // fallback to createElement approach
    if(!element) element = document.createElement(elementName);
    
    // abort if nothing could be created
    if(!element) return;

    // attributes (or text)
    if(arguments[1])
      if(this._isStringOrNumber(arguments[1]) ||
        (arguments[1] instanceof Array)) {
          this._children(element, arguments[1]);
        } else {
          var attrs = this._attributes(arguments[1]);
          if(attrs.length) {
            try { // prevent IE "feature": http://dev.rubyonrails.org/ticket/2707
              parentElement.innerHTML = "<" +elementName + " " +
                attrs + "></" + elementName + ">";
            } catch(e) {}
            element = parentElement.firstChild || null;
            // workaround firefox 1.0.X bug
            if(!element) {
              element = document.createElement(elementName);
              for(attr in arguments[1]) 
                element[attr == 'class' ? 'className' : attr] = arguments[1][attr];
            }
            if(element.tagName != elementName)
              element = parentElement.getElementsByTagName(elementName)[0];
            }
        } 

    // text, or array of children
    if(arguments[2])
      this._children(element, arguments[2]);

     return element;
  },
  _text: function(text) {
     return document.createTextNode(text);
  },
  _attributes: function(attributes) {
    var attrs = [];
    for(attribute in attributes)
      attrs.push((attribute=='className' ? 'class' : attribute) +
          '="' + attributes[attribute].toString().escapeHTML() + '"');
    return attrs.join(" ");
  },
  _children: function(element, children) {
    if(typeof children=='object') { // array can hold nodes and text
      children.flatten().each( function(e) {
        if(typeof e=='object')
          element.appendChild(e)
        else
          if(Builder._isStringOrNumber(e))
            element.appendChild(Builder._text(e));
      });
    } else
      if(Builder._isStringOrNumber(children)) 
         element.appendChild(Builder._text(children));
  },
  _isStringOrNumber: function(param) {
    return(typeof param=='string' || typeof param=='number');
  }
}

Effect.BackgroundScroll = Class.create();
Object.extend(Object.extend(Effect.BackgroundScroll.prototype, Effect.Base.prototype), {
  initialize: function(element) {
    this.element = $(element);
    if(!this.element.currentBackgroundPosition)
      this.element.currentBackgroundPosition = [0, 69];
    this.offsets = arguments[1];
    this.start(arguments[2] || {});
  },
  setup: function() {
    this.current = this.element.currentBackgroundPosition;
    this.delta = [
      this.offsets[0] - this.current[0],
      this.offsets[1] - this.current[1]];
  },
  update: function(position) {
    this.element.currentBackgroundPosition = [
      Math.round(this.current[0] + (this.delta[0]*position)),
      Math.round(this.current[1] + (this.delta[1]*position)) ];
    this.element.style.backgroundPosition = 
      this.element.currentBackgroundPosition[0] + 'px ' +
      this.element.currentBackgroundPosition[1] + 'px';
  }
});

Effect.ScrollTo = Class.create();
Object.extend(Object.extend(Effect.ScrollTo.prototype, Effect.Base.prototype), {
  initialize: function(element) {
    this.element = $(element);
    this.start(arguments[1] || {});
  },
  setup: function() {
    Position.prepare();
    var offsets = Position.cumulativeOffset(this.element);
    if(this.options.offset) offsets[0] += this.options.offset;
    var max = window.innerWidth ? 
      window.width - window.innerWidth :
      document.documentElement.scrollWidth - 
        (document.documentElement.clientWidth ? 
          document.documentElement.clientWidth : document.body.clientWidth);
    this.scrollStart = Position.deltaX;
    this.delta = (offsets[0] > max ? max : offsets[0]) - this.scrollStart;
  },
  
  update: function(position) {
    Position.prepare();
    var offset = this.scrollStart + (position*this.delta);
    if(Engine.isMSIE) {
      document.documentElement.scrollLeft=offset;
    }
    else
      window.scrollTo(offset, position.deltaY);
    
  }
});



function doeet(x,element) {
  new Effect.BackgroundScroll(element, [0, -((x*371)-69)], { duration: .5 });
}