function ShowLayer(wert)
  {
       if (document.layers)
       {
            obj = eval("document."+wert);
       }
       else
       {
            obj = document.getElementById(wert);
            obj = obj.style;
       }
       obj.visibility = "visible";
 }
function UnshowLayer(wert)
  {
       if (document.layers)
       {
            obj = eval("document."+wert);
       }
       else
       {
            obj = document.getElementById(wert);
            obj = obj.style;
       }
       obj.visibility = "hidden";
  }