$(function () {
	/*
		dropdown menu
	*/
	var mousein = 0;

	$('table#p_nav a').hover(
		function () {
			var td = $(this).closest('td');
			var offset = td.offset();
			var menu = $($("div.menu").get($('table#p_nav td').index(td[0])));
			var lastMenu = $('div.menu:visible');			// 得到上一个
			mousein++;


			if (menu.html() != lastMenu.html()) lastMenu.hide('fast');	// 隐藏上一个
			if (menu.children().size() > 0) {
				menu.css('top', offset.top + td.height()).css('left', offset.left).show('fast');
			}
			
		},
		function () {mousein--;}
	);

	$('table#p_nav a').mousemove(function(event) {event.stopPropagation()});
	$('div.menu').mousemove(function(event) {event.stopPropagation()});

	$('div.menu').hover(
		function() {mousein++},
		function() {mousein--;}
	);

	$(document).mousemove(function() {if (mousein == 0) $('div.menu:visible').hide('fast');});
});