Rollover = Class.create();
Rollover.prototype=
{
	initialize: function(imageID, prefix)
	{
		var arr = imageID.split('_');
		this.el = $(imageID);	
		this.imgOff = new Image();
		this.imgOff.src = '/images/menu/' + prefix + '_' + arr[1] + '.gif';
		this.imgOn = new Image();
		this.imgOn.src = '/images/menu/' + prefix + '_' + arr[1] + '_over.gif';
		this.setEvent();
	},
	setEvent:function()
	{
		Event.observe
		(
			this.el,
			'mouseover',
			function(event)
			{
				var el = Event.element(event);
				el.src = this.imgOn.src;
			}.bindAsEventListener(this)
		);
		Event.observe
		(
			this.el,
			'mouseout',
			function(event)
			{
				var el = Event.element(event);
				el.src = this.imgOff.src;
			}.bindAsEventListener(this)
		);
	}
}