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

function menu_dropdown_open() {
	menu_dropdown_canceltimer();
	menu_dropdown_close();
	ddmenuitem = $(this).find('ul').css('visibility', 'visible');
}

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

function menu_dropdown_timer() {
	closetimer = window.setTimeout(menu_dropdown_close, timeout);
}

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

$(document).ready(function() {
	$('.menu_dropdown > li').hover(menu_dropdown_open,menu_dropdown_timer);
	$('.tab_menu_dropdown > li').hover(menu_dropdown_open,menu_dropdown_timer);
	$(document).click(menu_dropdown_close);
});