//Event.observe(window, 'load', rotateAdds, false);
setInterval("rotateAdds()", 10000);
<!-- /* $Id: ads.js 24736 2008-08-11 13:01:09Z ddamstra $ */ -->
function rotateAdds() {
	var one = $('one');
	var two = $('two');
	
	if(two.style.zIndex > one.style.zIndex) {
		var coming = two;
		var going = one;
	} else {
		var coming = one;
		var going = two;
	}
	
	coming.style.zIndex = 100;
	going.style.zIndex = 110;
	coming.style.display = 'block';
	
	var myAjax = new Ajax.Updater(
			coming, 
			'/ads/random', 
			{
				method: 'get',
				onSuccess: function() {
					Effect.Fade(going);
				}
			}
	);
}