function _menu(id)
{
    var id = id ? id : "main_nav";
    var menu = $(id).getElementsByTagName("ul");

    for (i = 0; i < menu.length; i++)
    {
    	var my_elem = menu[i];
    	my_elem.setAttribute("id","menu"+i);
    	if (my_elem.parentNode.nodeName == "LI")
    	{
	     	if (my_elem.previousSibling.previousSibling.firstChild)
	     	{
	     	    name =  my_elem.previousSibling.previousSibling.firstChild.id;
	     	}
	     	my_elem.parentNode.onmouseover = function ()
		    {
			    this.lastChild.style.display = "block";
    		}
	    	my_elem.parentNode.onmouseout = function ()
		    {
			    this.lastChild.style.display= "none";
    		}
    		my_elem.parentNode.lastChild.onmouseover = function ()
		    {
			    document.getElementById(name).src = eval(name + "_h.src");
    		}
    		my_elem.parentNode.lastChild.onmouseout = function ()
		    {
			    document.getElementById(name).src = eval(name + "_n.src");
			}
	    }
    }
}
function over_ev(ev, id)
{
    over(id);
}
function out_ev(ev, id)
{
    out(id);
}


function menu(id)
{
    var id = id ? id : "main_nav";
    var menu = $(id).getElementsByTagName("ul");

    for (i = 0; i < menu.length; i++)
    {
    	var my_elem = $(menu[i]);
    	my_elem.setAttribute("id","menu"+i);
    	if (my_elem.parentNode.nodeName == "LI")
    	{
            Element.hide(my_elem.parentNode.lastChild);
            $(my_elem.parentNode.lastChild).removeClassName("hidden");
	     	if (my_elem.previousSibling.previousSibling.firstChild)
	     	{
	     	    img =  my_elem.previousSibling.previousSibling.firstChild.id;
	     	}
	     	Event.observe(my_elem.parentNode, "mouseover", function (){
			    Element.show(this.lastChild);
    		});
	     	Event.observe(my_elem.parentNode, "mouseout", function (){
			    Element.hide(this.lastChild);
    		});
    		Event.observe(my_elem.parentNode.lastChild, "mouseover", over_ev.bindAsEventListener(this,img));
            Event.observe(my_elem.parentNode.lastChild, "mouseout", out_ev.bindAsEventListener(this,img));
	    }
    }
}

Event.observe(window, 'load', function() { menu("main_nav") });