// grab URL, parse string to get product name

 var s = window.location.href;

 var stringTail = s.split("/");

function calling_ad(){

            var str = "/cd/channel/reseller/";

            var fullstr = str + stringTail[6]+"/"+stringTail[7]+"/sales/index.htm";

            document.getElementById('ad').innerHTML = "<a href="+fullstr+">Ad builder home</a>";

}