function fenster()
{
wer=navigator.appName.lastIndexOf("Microsoft");
if (wer>=0)
F=open('zaddguest.html','guest','width=500,height=432,screenX=40,screenY=40,dependend=yes,resizable=no');
else
F=open('zaddguest.html','guest','width=550,height=432,screenX=40,screenY=40,dependend=yes,resizable=yes');
F.focus();
}