var TimerId;
    var FirstLevel = 'x';
    var SecondLevel = 'x';
    var ThirdLevel = 'x';
    var FourthLevel;
    
    function setNavLevel(Lev1,Lev2,Lev3)
    {
      FirstLevel = Lev1;
      SecondLevel = Lev2;
      ThirdLevel = Lev3;      
    }
    
    function hideNavLevel(Lev1ID,Lev2ID,Lev3ID)
            {
      timerfunction = function(lev1,lev2,lev3)
              {
        if(lev1 != 'x')
              {
                var dingen = document.getElementById(lev1);
                dingen.style.visibility = 'hidden';
              }
        if(lev2 != 'x')
              {
          var dingen = document.getElementById(lev2);
                dingen.style.visibility = 'hidden';
              }
        if(lev3 != 'x')
              {
          var dingen = document.getElementById(lev3);
                dingen.style.visibility = 'hidden';
              }
            }
      TimerId = window.setTimeout("timerfunction('" + Lev1ID + "','" + Lev2ID + "','" + Lev3ID + "')",800);
    }
    
    function showNavLevel(Lev1,Lev2,Lev3)
    {
      clearTimeout(TimerId);
      if(document.getElementById) 
      {
        if(FirstLevel != 'x')
    {
          document.getElementById(FirstLevel).style.visibility = 'hidden';
          FirstLevel = 'x';
    }
        if(Lev1 != 'x')
    {
          document.getElementById(Lev1).style.visibility = 'visible';
          FirstLevel = Lev1;
    }

        if(SecondLevel != 'x')
    {
          document.getElementById(SecondLevel).style.visibility = 'hidden';
          SecondLevel = 'x';
    }
        if(Lev2 != 'x')
    {
          document.getElementById(Lev2).style.visibility = 'visible';
      SecondLevel = Lev2;
    }

        if(ThirdLevel != 'x')
    {
          document.getElementById(ThirdLevel).style.visibility = 'hidden';
          ThirdLevel = 'x';
    }
        if(Lev3 != 'x')
    {
          document.getElementById(Lev3).style.visibility = 'visible';
      ThirdLevel = Lev3;
    }
      }
    }