function MitteFenster(dateiname,b,h)
{
var eigenschaft,sbreite,shoehe,fenster;

sbreite = screen.width;
shoehe = screen.height;

x = (sbreite-b)/2;
y = (shoehe-h)/2;

eigenschaften="left="+x+",top="+y+",screenX="+x+",screenY="+y+",width="+b+",height="+h+",menubar=no,toolbar=no";
fenster=window.open(dateiname,"Titel",eigenschaften);
fenster.focus();
}