import flash.external.ExternalInterface;

btn.onRelease=gotoAd;

function gotoAd(){


    var vid:String = String(ExternalInterface.call("function(){return (typeof getVidForFlash =='undefined')?'':getVidForFlash();}"));
    var url:String = _root.clickTag
    if(vid){
    url+="&Custom1=" + vid;
    }
    getURL(url, "_blank");
}