var adInterval = 7;
var adNumber = 3;
var adCurrentIndex = 0;

$(document).ready(
	function () {

		// Start rotating ads
		setInterval("nextAd()",adInterval * 1000);
});


var nextAd = function() {
	$('div#ad_'+adCurrentIndex).hide();
	adCurrentIndex = (adCurrentIndex + 1) % adNumber;
	$('div#ad_'+adCurrentIndex).fadeIn();
};