var timeout = 500;
var closetimer;
var current;

function dropnav_open(){
	dropnav_canceltimer();
	dropnav_close();
	current = $(this).find('ul').css('visibility', 'visible');
}

function dropnav_close(){
	if (current) 
		current.css('visibility', 'hidden');
}

function dropnav_timer(){
	closetimer = window.setTimeout(dropnav_close, timeout);
}

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

$(document).ready(function(){
	$('#dropnav > li').bind('mouseover', dropnav_open);
	$('#dropnav > li').bind('mouseout', dropnav_timer);
	$(document).bind('click', dropnav_close);
});