function newwindow (adress, w, h, name)
  {
  x = (screen.availWidth - w) / 2;
  y = (screen.availHeight - h) / 2;
  options = 'width=' + w + ',height=' + h + ',left=' + x + ', top=' + y + ', menubar=no, resizable=no';
  Fenster = window.open(adress, name, options);
  Fenster.focus()
  }