function tree_menu()
{
  if (document.getElementById("navigation-container"))
  {
    var menu = document.getElementById("navigation-container");
    if (menu.childNodes.length > 0)
    {
      var li = menu.getElementsByTagName("li");
      if (li.length > 0)
      {
        for (var i = 0; i < li.length; i++)
        {
          var node = li[i];
          for (var j = 0; j < node.childNodes.length; j++)
          {
            if (node.childNodes[j].nodeName.toLowerCase() == "a")
            {
              var a = node.childNodes[j];
              if (node.getElementsByTagName("ul").length > 0)
              {
                node.className = "close";
                a.sender = node;
				a.onclick = function()
                {
                this.sender.className = (this.sender.className == "open") ? "close" : "open";
                };
              }
              else
              {
                // li[i].className = "no_children";
              }                          
            }
          }
        }    
      }
    }
  }
}