var listChanger = Class.create();
listChanger.prototype =
{
     initialize:function(holderId, className)
     {
          this.changer 	= document.getElementById(holderId).getElementsByTagName("select")[0];
          this.elements	= document.getElementsByClassName(className, holderId);
          this.currentIndex	= 0;

		var index = Cookie.get(holderId + "_last_selected_index_in_cookie");
          var thisCopy = this;

		if(index)
		{
		     this.currentIndex = index;
		}

		this.options = this.changer.getElementsByTagName("option");
		this.options[this.currentIndex].selected = true;
		for( var i=0; i < this.elements.length; i++ )
		{
			Element.hide( this.elements[i] );
		}
		Element.show( this.elements[this.currentIndex] );

    		Event.observe
    		(
    			this.changer,
    			"change",
    			function(event)
    			{
    				thisCopy.changeOption();
    			}
    		);

    		Event.observe
    		(
    			this.changer,
    			'keypress',
    			this.checkKey.bindAsEventListener(this)
    		);
     },

	checkKey: function(event)
	{
		var code = event.keyCode;
		if(code == Event.KEY_UP || code == Event.KEY_LEFT )
		{
			if( (this.currentIndex - 1 ) > -1 )
			{
				this.changer.selectedIndex = this.currentIndex - 1;
			}
			if( navigator.userAgent.indexOf('MSIE') != -1 && code == Event.KEY_UP )
			{
				this.changer.selectedIndex += 1;
			}
			this.changeOption() ;
		}

		if(code == Event.KEY_DOWN || code == Event.KEY_RIGHT )
		{
			if( (this.currentIndex + 1 ) < this.options.length )
			{
				this.changer.selectedIndex = this.currentIndex + 1;
			}
			if( navigator.userAgent.indexOf('MSIE') != -1 && code == Event.KEY_DOWN )
			{
				this.changer.selectedIndex -= 1;
			}
			this.changeOption() ;
		}
	},

	changeOption: function()
	{
		if( this.currentIndex != this.changer.selectedIndex )
		{
			Element.hide( this.elements[ this.currentIndex ] );
			this.currentIndex = this.changer.selectedIndex;
			Element.show( this.elements[this.currentIndex] );
			Cookie.set( this.changer.parentNode.id + "_last_selected_index_in_cookie", this.currentIndex, 30);
		}
	}
}