Have a look at code delivered by Superfish:
https://www.superfish.com/ws/sf_preloader.jsp
https://www.superfish.com/ws/sf_code.jsp
And grep for track and retarget. Just two snippets:
var url = sfDomain + "trackSession.action?userid=" + similarproducts.b.qsObj.userid + "&sessionid=-10&action=ud_host_failed";
and: function isRetargetingEnabled(){
if( similarproducts.b.enableRetargetingUnit && !isRetargetingBlackList()){
return 1;
} else{
return 0;
}
}