Event.observe(window, 'load', function() {
	showRandomBanner();
	setTimeout('showRandomBanner()',15000);
});

function showRandomBanner() {
	var bans = $$('#banners div.banner');
	bans.each(function(el) {
		el.hide();
	});
	var shownum = Math.floor(Math.random()*(bans.length));
	bans[shownum].show();
	setTimeout('showRandomBanner()',15000);
}