var timeout         = 500;
var closetimer		= 0;
var ddmenuitem      = 0;

function topnav_open()
{	topnav_canceltimer();
    topnav_close();
    ddmenuitem = $(this).find('ul').eq(0).css('visibility', 'visible');}

function topnav_close()
{	if(ddmenuitem) ddmenuitem.css('visibility', 'hidden');}

function topnav_timer()
{	closetimer = window.setTimeout(topnav_close, timeout);}

function topnav_canceltimer()
{	if(closetimer)
    {	window.clearTimeout(closetimer);
    	closetimer = null;}}

$(document).ready(function()
{	$('#top-nav > li').bind('mouseover', topnav_open);
    $('#top-nav > li').bind('mouseout',  topnav_timer);});

document.onclick = topnav_close;