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

function Nav_open() {
	Nav_canceltimer();
	Nav_close();
	ddmenuitem = $(this).find('ul').css('visibility', 'visible');
}

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

function Nav_timer() {
	closetimer = window.setTimeout(Nav_close, timeout);
}

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

$(document).ready(function() {
	$('#Nav > li').bind('mouseover', Nav_open)
	$('#Nav > li').bind('mouseout',  Nav_timer)
});

document.onclick = Nav_close;