// *************************
function hideSubmenus()
{
  // variables
  var mainMenu = document.getElementById('dropdownmenu');
  var i = 0;

  // find submenu element
  while (mainMenu.childNodes.length > i)
  {
    if (mainMenu.childNodes.item(i).className.indexOf('mainitem') != -1)
    {
      var elmSubmenu = getSubmenu(mainMenu.childNodes.item(i));
      if (elmSubmenu != null)
      {
        if (elmSubmenu.style.display == '')
          elmSubmenu.style.display == 'none';
      }
    }
    i++;
  }
}

// *************************
function getSubmenu(elm)
{
  var i = 0;

  // find submenu element
  while (elm.childNodes.length > i)
  {
    if (elm.childNodes.item(i).className == 'submenu')
      return elm.childNodes.item(i);
    i++;
  }
  return null;
}

// *************************
function submenu_show(elm)
{
  hideSubmenus();
  var elmSubmenu = getSubmenu(elm);

  if (elmSubmenu != null)
    elmSubmenu.style.display = '';
}

// *************************
function submenu_hide(elm)
{
  var elmSubmenu = getSubmenu(elm);

  if (elmSubmenu != null)
    elmSubmenu.style.display = 'none';
}