function ScreenIt(url,name,parm)
{ 
 if(url.indexOf("/sys/popup_source.shtml?Category=")!=-1) return false; 
 if(url.indexOf("/sys/popup_source.shtml")!=-1) return false; 
 if(url.indexOf("/doc/general/angelfire_popunder.html")!=-1) return false;
 return window.Xopen(url,name,parm); 
} 

window.Xopen=window.open; 
window.open=ScreenIt;