function zeige(ebene)
{
  if (document.layers)
    document.layers[ebene].visibility = "visible";
  if (document.all)
    document.all[ebene].style.visibility = "visible";
  if (document.getElementById)
   document.getElementById(ebene).style.visibility = "visible";  
}

function verstecke(ebene)
  {
  if (document.layers)
    document.layers[ebene].visibility = "hidden";
  if (document.all)
    document.all[ebene].style.visibility = "hidden";
  if(document.getElementById)
   document.getElementById(ebene).style.visibility = "hidden";
  }