var activeMenu = null;




function hideActive()
{
  if (activeMenu !== null)
  {
    hideIt(activeMenu);
    activeMenu = null;
  }
}



function popMenu(obj)
{
  hideActive();
  activeMenu = document.getElementById(obj);
  showIt(activeMenu);
}



function hideIt(obj)
{
  obj.style.visibility = "hidden";
}



function showIt(obj)
{
  obj.style.visibility = "visible";
}