function Fenster(dateiname,b,h) 
      {
      var eigenschaft,sbreite,shoehe,fenster;
      sbreite = screen.width;
      shoehe = screen.height;
      x = (sbreite-b)/2;
      y = 300;
      eigenschaften="left="+x+",top="+y+",screenX="+x+",screenY="+y+",width="+b+",height="+h+",menubar=no,toolbar=no,scrollbars=no";
      fenster=window.open(dateiname,"Titel",eigenschaften);
      fenster.focus();
            }