var sichtbar = "null";
var Timer;

function show(sub) {
 if(document.getElementById)
  {
   if (sichtbar != "null")
    {
    clearTimeout(Timer);
    document.getElementById(sichtbar).style.display = "none";
    }
   document.getElementById(sub).style.display = "inline";
   sichtbar = sub;
  }
}

function hide(sub) {
 Timer = setTimeout('zu()',800);
}

function zu() {
  document.getElementById(sichtbar).style.display = "none";
  sichtbar = "null";
 }