var timeout = 500;
var close = 0;
var menuitem = 0;

function menu_open()
{
	menu_cancel();
	menu_close();
	menuitem = $(this).find('ul').css('visibility', 'visible');
}

function menu_close()
{
	if(menuitem) menuitem.css('visibility', 'hidden');
}

function menu_timer()
{
	close = window.setTimeout(menu_close, timeout);
}

function menu_cancel()
{
	if(close)
	{
		window.clearTimeout(close);
		close = null;
	}
}

$(document).ready(function()
{
	$('#nav > li').bind('mouseover', menu_open)
	$('#nav > li').bind('mouseout',  menu_timer)
});

document.onclick = menu_close;