Math.randomMax = function(maxVal,asFloat){
var val = Math.random()*maxVal;
return asFloat?val:Math.round(val);
}
function rotateAds(){
var adArray = new Array();
var random = Math.randomMax(100);
var offset = 0;
var count = adArray.length;
for (i = 0; i < count; i++) {
offset += adArray[i][1];
if (random <= offset) {
document.write('<scr'+'ipt type="text/javascript" src="'+adArray[i][0]+'" ></scr'+'ipt>'); 
return;
 }   } } 
rotateAds();