function zoom(url,breite,hoehe) 
{ 
 
var X = (screen.availWidth - breite) / 2 
var Y = (screen.availHeight - hoehe) / 2 

window.open(url,"zoom","width=" + breite + ",height=" + hoehe + ",innerWidth=" + breite + ",innerHeight=" + hoehe + ",menubar=0,scrollbars=0,resizable=0,location=0,status=0,directories=0,left=" + X + ",screenX=" + X + ",top=" + Y + ",screenY=" + Y + ",dependent") 
}