可以设置一个一直都显示的二级菜单，修复了没有二级菜单时鼠标移上去仍然显示上一个二级菜单的问题.支持一级菜单鼠标离开事件
html代码
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>我的网站</title>
<meta name="description" content="" />
<meta name="keywords" content="" />
<link type="text/css" rel="stylesheet" href="http://www.188163.com/img/fnews/css/style.css" />
</head>
<body>
<div>
<div>
<>
<>
<div id="menu">
<ul>
<>
<li><a href="/" rel='dropmenu1'>主 页</a></li>
<li><a href='/a/jinrongzixun/'>金融资讯</a></li>
<li><a href='/a/gerenjinrong/' rel='dropmenu2'>个人金融</a></li>
<li><a href='/a/qiyejinrong/' rel='dropmenu4'>企业金融</a></li>
<li><a href='/a/caijingpindao/' rel='dropmenu5'>财经频道</a></li>
<li><a href='/a/zhifujiesuan/' rel='dropmenu6'>支付结算</a></li>
<li><a href='/a/yewushenqingtongdao/' rel='dropmenu7'>业务申请</a></li>
<li><a href='/a/zhongyaogonggao/' >重要公告</a></li>
<li><a href='/a/xinyongka/' >信用卡</a></li>
</ul>
</div>
<div>
</div>
<>
<script type="text/javascript" src="dropdown.js"></script>
<ul id="dropmenu1">
<li><a href="/a/gerenjinrong/touzilicai/">首页列表</a> | </li>
</ul>
<ul id="dropmenu2">
<li><a href="/a/gerenjinrong/touzilicai/">投资理财</a> | </li>
<li><a href="/a/gerenjinrong/grdk/">个人贷款</a> | </li>
<li><a href="/a/gerenjinrong/gerenxiaofei/">个人消费贷款</a> | </li>
<li><a href="/a/gerenjinrong/xinyong/">信用贷款</a> | </li>
<li><a href="/a/gerenjinrong/qichedaikuan/">汽车贷款</a> | </li>
<li><a href="/a/gerenjinrong/yishoulou/">一手楼按揭</a> | </li>
<li><a href="/a/gerenjinrong/ershoulou/">二手楼按揭</a> | </li>
<li><a href="/a/gerenjinrong/grjy/">个人经营贷款</a> | </li>
</ul>
<ul id="dropmenu4">
<li><a href="/a/qiyejinrong/gongsirongzi/">公司融资</a> | </li>
<li><a href="/a/qiyejinrong/maoyirongzi/">贸易融资</a> | </li>
<li><a href="/a/qiyejinrong/gongsilicai/">公司理财</a> | </li>
<li><a href="/a/qiyejinrong/piaojuyewu/">票据业务</a> | </li>
<li><a href="/a/qiyejinrong/xiangmurongzi/">项目融资</a> | </li>
</ul>
<ul id="dropmenu5">
<li><a href="/a/caijingpindao/huangjin/">黄金</a> | </li>
<li><a href="/a/caijingpindao/zhaiquan/">债券</a> | </li>
<li><a href="/a/caijingpindao/waihui/">外汇</a> | </li>
<li><a href="/a/caijingpindao/jijin/">基金</a> | </li>
</ul>
<ul id="dropmenu6">
<li><a href="/a/zhifujiesuan/pos/">P0S支付</a> | </li>
</ul>
<ul id="dropmenu7">
<li><a href="/a/yewushenqingtongdao/gerenyewu/">个人业务咨询</a> | </li>
<li><a href="/a/yewushenqingtongdao/gongsiyewu/">公司业务咨询</a> | </li>
</ul>
<ul id="dropmenu8">
</ul>
<ul id="dropmenu3">
</ul>
<script type="text/javascript"> cssdropdown.startchrome("menu")</script>
</div>
</div>
<>
</body>
</html>
dropdown.js
var cssdropdown = {
disappeardelay: 250,
disablemenuclick: false,
enableswipe: 1,
enableiframeshim: 1,
dropmenuobj: null,
ie: document.all,
firefox: document.getElementById && !document.all,
swipetimer: undefined,
bottomclip: 0,
getposOffset: function(what, offsettype) {
var totaloffset = (offsettype == "left") ? what.offsetLeft: what.offsetTop;
var parentEl = what.offsetParent;
while (parentEl != null) {
totaloffset = (offsettype == "left") ? totaloffset + parentEl.offsetLeft: totaloffset + parentEl.offsetTop;
parentEl = parentEl.offsetParent;
}
return totaloffset;
},
swipeeffect: function() {
if (this.bottomclip < parseInt(this.dropmenuobj.offsetHeight)) {
this.bottomclip += 10 + (this.bottomclip / 10);
this.dropmenuobj.style.clip = "rect(0 auto " + this.bottomclip + "px 0)";
} else return;
this.swipetimer = setTimeout("cssdropdown.swipeeffect()", 10);
},
//隐藏或者显示二级菜单
showhide: function(obj, e) {
if (this.ie || this.firefox) this.dropmenuobj.style.left = this.dropmenuobj.style.top = "-500px";
if (e.type == "click" && obj.visibility == hidden || e.type == "mouseover") {
if (this.enableswipe == 1) {
if (typeof this.swipetimer != "undefined") clearTimeout(this.swipetimer);
obj.clip = "rect(0 auto 0 0)";
this.bottomclip = 0;
this.swipeeffect();
}
obj.visibility = "visible";
} else if (e.type == "click") obj.visibility = "hidden";
},
iecompattest: function() {
return (document.compatMode && document.compatMode != "BackCompat") ? document.documentElement: document.body;
},
clearbrowseredge: function(obj, whichedge) {
var edgeoffset = 0;
if (whichedge == "rightedge") {
var windowedge = this.ie && !window.opera ? this.iecompattest().scrollLeft + this.iecompattest().clientWidth - 15 : window.pageXOffset + window.innerWidth - 15;
this.dropmenuobj.contentmeasure = this.dropmenuobj.offsetWidth;
if (windowedge - this.dropmenuobj.x < this.dropmenuobj.contentmeasure) edgeoffset = this.dropmenuobj.contentmeasure - obj.offsetWidth;
} else {
var topedge = this.ie && !window.opera ? this.iecompattest().scrollTop: window.pageYOffset;
var windowedge = this.ie && !window.opera ? this.iecompattest().scrollTop + this.iecompattest().clientHeight - 15 : window.pageYOffset + window.innerHeight - 18;
this.dropmenuobj.contentmeasure = this.dropmenuobj.offsetHeight;
if (windowedge - this.dropmenuobj.y < this.dropmenuobj.contentmeasure) {
edgeoffset = this.dropmenuobj.contentmeasure + obj.offsetHeight;
if ((this.dropmenuobj.y - topedge) < this.dropmenuobj.contentmeasure) edgeoffset = this.dropmenuobj.y + obj.offsetHeight - topedge;
}
}
return edgeoffset;
},
//鼠标移动到一级菜单上执行
dropit: function(obj, e, dropmenuID) {
//隐藏上次显示的二级菜单
if (this.dropmenuobj != null) this.dropmenuobj.style.visibility = "hidden";
this.clearhidemenu();
if (this.ie || this.firefox) {
var me = this;
//一级菜单鼠标离开事件
obj.onmouseout = function() {
cssdropdown.delayhidemenu();
};
//一级菜单鼠标点击事件
obj.onclick = function() {
return ! cssdropdown.disablemenuclick
};
if (!dropmenuID) {
return;
}
this.dropmenuobj = document.getElementById(dropmenuID);
if (!this.dropmenuobj) return;
//为二级菜单绑定鼠标移动到事件
this.dropmenuobj.onmouseover = function() {
//移除从一级菜单离开时触发的方法，防止误执行
cssdropdown.clearhidemenu();
}
//为二级菜单绑定鼠标离开事件
this.dropmenuobj.onmouseout = function(e) {
cssdropdown.dynamichide(e);
}
//为二级菜单绑定鼠标点击事件
this.dropmenuobj.onclick = function() {
cssdropdown.delayhidemenu();
}
this.showhide(this.dropmenuobj.style, e);
//调整二级菜单位置，以免位置错乱
this.dropmenuobj.x = this.getposOffset(obj, "left");
this.dropmenuobj.y = this.getposOffset(obj, "top");
this.dropmenuobj.style.left = this.dropmenuobj.x - this.clearbrowseredge(obj, "rightedge") + "px";
this.dropmenuobj.style.top = this.dropmenuobj.y - this.clearbrowseredge(obj, "bottomedge") + obj.offsetHeight + 1 + "px";
this.positionshim();
}
},
positionshim: function() {
if (this.enableiframeshim && typeof this.shimobject != "undefined") {
if (this.dropmenuobj.style.visibility == "visible") {
this.shimobject.style.width = this.dropmenuobj.offsetWidth + "px";
this.shimobject.style.height = this.dropmenuobj.offsetHeight + "px";
this.shimobject.style.left = this.dropmenuobj.style.left;
this.shimobject.style.top = this.dropmenuobj.style.top;
}
this.shimobject.style.display = (this.dropmenuobj.style.visibility == "visible") ? "block": "none";
}
},
hideshim: function() {
if (this.enableiframeshim && typeof this.shimobject != "undefined") this.shimobject.style.display = 'none';
},
contains_firefox: function(a, b) {
while (b.parentNode) if ((b = b.parentNode) == a) return true;
return false;
},
//隐藏二级菜单，兼容性处理
dynamichide: function(e) {
var evtobj = window.event ? window.event: e;
//确认是鼠标离开事件，避免误触发
if (this.ie && !this.dropmenuobj.contains(evtobj.toElement)) this.delayhidemenu();
else if (this.firefox && e.currentTarget != evtobj.relatedTarget && !this.contains_firefox(evtobj.currentTarget, evtobj.relatedTarget)) this.delayhidemenu();
},
//鼠标点击菜单，或者离开菜单时执行
delayhidemenu: function() {
this.delayhide = setTimeout(function() {
cssdropdown.dropmenuobj.style.visibility = 'hidden';
cssdropdown.hideshim();
cssdropdown.showAlways();
},
this.disappeardelay);
},
//移除定时方法
clearhidemenu: function() {
if (this.delayhide != "undefined") clearTimeout(this.delayhide);
},
//显示默认被选中的一级菜单
showAlways: function() {
if (this.always) {
this.always.onmouseover({
type: "mouseover"
});
}
},
//初始化
startchrome: function() {
for (var ids = 0; ids < arguments.length; ids++) {
var menuitems = document.getElementById(arguments[ids]).getElementsByTagName("a");
for (var i = 0; i < menuitems.length; i++) {
var relvalue = menuitems[i].getAttribute("rel");
//绑定鼠标移动到事件
menuitems[i].onmouseover = function(e) {
var event = typeof e != "undefined" ? e: window.event;
cssdropdown.dropit(this, event, this.getAttribute("rel"));
};
//显示默认被选中的一级菜单
if (!this.always && menuitems[i].parentNode.getAttribute("class") == "navselect") {
this.always = menuitems[i];
this.showAlways();
}
}
}
if (window.createPopup && !window.XmlHttpRequest) {
document.write('<IFRAME id="iframeshim" src="" frameBorder="0" scrolling="no"></IFRAME>');
this.shimobject = document.getElementById("iframeshim");
}
}
}
演示地址：http://www.188163.com（我不知道啥时候失效...）