function popOpen(url, breite, hoehe) {
      // Errechnet Koordinaten, um das Popup zentriert zu platzieren
      //links = (screen.width/2)-(breite/2);
      oben = (screen.height/2)-(hoehe/2);
      window.open(url,"popup","height="+hoehe+",width="+breite+",status = no,toolbar = no,menubar = no,location = no,resizable = no,titlebar = no,scrollbars = no,fullscreen = no,top ="+oben+",left =20");
  }