var sid='cpt';
var url=window.location;
var referer=document.referer;
var mydiv = document.getElementById("mydiv");
var img1 = '<img style="width:0px;height:0px" src="http://cms.chinacpt.com/portal/access.service?sid=' + sid + '&url=' + url + '&referer=' + referer + '"/>';
mydiv.innerHTML = img1;