var AD_REFRESH_TIME_MS = 300000;

cworld={

	addEvent: function(elm, evType, fn, useCapture){	
		if (elm.addEventListener){
			elm.addEventListener(evType, fn, useCapture);
			return true;
		} else if (elm.attachEvent) {
			var r = elm.attachEvent('on' + evType, fn);
			return r;
		} else {
			elm['on' + evType] = fn;
		}
	}
}

function stripDARTKeyValue(url, key) {
	var idx = url.indexOf(key);
	var nextSemiColonIdx = url.indexOf(";", idx);
		
	if (idx > 0) {
		return url.substring(0, idx) + url.substring(nextSemiColonIdx+1,url.length);
	}
	else {
		return url;
	}
}


function addRandomKeyValue(url) {
	url = stripDARTKeyValue(url, "rnd");
	var idx = url.indexOf(";");
	var rnd =  parseInt(Math.random() * 1000000);
	
	return url.substring(0,idx) + ";rnd=" + rnd + url.substring(idx,url.length);
}


function reloadAd(iFrameId) {
	self.setTimeout(
		function () { 
			if (document.getElementById(iFrameId)) {
				var oldSrc = document.getElementById(iFrameId).src;
				if(oldSrc){
					var newSrc = addRandomKeyValue(oldSrc);			
					document.getElementById(iFrameId).src = "";
					document.getElementById(iFrameId).src = newSrc;
				}
				
			}
			reloadAd(iFrameId); 
		}, AD_REFRESH_TIME_MS);
}