function fenster(file, breite, hoehe) {
x = breite;
y = hoehe;
popup = window.open(file,'Fenster','toolbar=no,location=no,directories=no,status=no,copyhistory=no,scrollbars=no,resizable=no,width='+x+',height='+y);
if (popup.opener == null) popup.opener = window;
}