var timer;
 var i;
 var menuId;
 var dom = document.getElementById ? true : false;
 var ie4 = ((document.all) && (!dom)) ? true : false;
 var ns4 = document.layers ? true : false;
 var opera = navigator.userAgent.indexOf('Opera') != -1 ? true : false;
 var dhtml = dom ? true : ie4 ? true : ns4 ? true : false;
 var pocet = 18;

 function setVisibility(element, newVisibility)
  { 
   if (dhtml)
    {
     if (dom) document.getElementById(element).style.visibility = newVisibility;
     else if (ie4) document.all[element].style.visibility = newVisibility;
     else if (ns4) eval('document.' + element + '.visibility = newVisibility');
    }
  }
 function menu()
  {
   if (dhtml)
    {
     if (opera) for (i = 1; i <= pocet; i++) document.getElementById('hiddenMenu' + i).style.top = 20;
     if (ie4) for (i = 1; i <= pocet; i++) document.all['hiddenMenu' + i].style.top = 18;
     setVisibility('menuHolder','visible');
    }
  }
  
 function showMenu(id)
  {
   if (dhtml)
    {
     clearTimeout(timer);
     for (i = 1; i <= pocet; i++) if (i != id) setVisibility((ns4 ? 'menuHolder.document.' : '') + 'hiddenMenu' + i,'hidden');
     setVisibility((ns4 ? 'menuHolder.document.' : '') + 'hiddenMenu' + id,'visible');
    }
  }
 function hideMenu(id)
  {
   if (dhtml)
    {
     menuId = (ns4 ? 'menuHolder.document.' : '') + 'hiddenMenu' + id;
     timer = setTimeout("setVisibility(menuId,'hidden')", 50);
    }
  }
 function dontHideMenu()
  {
   if (dhtml) clearTimeout(timer);
  }