var Rollover = {
	initialized : false,
	rollovers : null,
	
	initialize : function() {
		if (!this.initialized) {
			this.rollovers = $$('.rollover');
			if (this.rollovers && this.rollovers.length) {
				for (var i=0; i<this.rollovers.length; i++) {
					if (this.rollovers[i].src) {
						var src = this.rollovers[i].src;
					} else {
						var src = this.rollovers[i].getStyle('backgroundImage');
					}
					this.rollovers[i].observe('mouseover', this.mouseover);
					this.rollovers[i].observe('mouseout', this.mouseout);
					var s = src.substring(0, src.lastIndexOf('.'));
					var e = src.substring(src.lastIndexOf('.'), src.length);
					this.rollovers[i]._osrc = s + '_over' + e;
					this.rollovers[i]._src = src;
				}
			}
			this.initialized = true;
		}
	},
	
	mouseover : function(event) {
		var e = Event.element(event);
		if (!e.hasClassName('rollover')) {
			e = e.up('.rollover');
		}
		e.addClassName('hover');
		if (e.src) {
			e.src = e._osrc;
		} else {
			e.setStyle({
				backgroundImage: e._osrc
			});
		}
	},
	
	mouseout : function(event) {
		var e = Event.element(event);
		if (!e.hasClassName('rollover')) {
			e = e.up('.rollover');
		}
		e.removeClassName('hover');
		if (e.src) {
			e.src = e._src;			
		} else {
			e.setStyle({
				backgroundImage: e._src
			});
		}
	}
}
Event.observe(window, 'load', function() {
	Rollover.initialize();
});