function karten_1()
  {
  if(navigator.appName == "Microsoft Internet Explorer")
    {
    window.open("karten1_1.htm","Seekarten","menubar=yes,left=0,top=0,height=570,width=700,resizable=yes");
    }
  else
    {
    window.open("karten2_1.htm","Seekarten","menubar=yes,left=0,top=0,height=570,width=700,resizable=yes");
    }
  }