js实现菜单折叠导航

<style type="text/css">

<!--

*{margin:0;padding:0;border:0;}

body {

font-family: arial, 宋体, serif;

font-size:12px;

}

#nav {

width:180px;

line-height: 24px;

list-style-type: none;

text-align:left;

/*定义整个ul菜单的行高和背景色*/

}

/*==================一级目录===================*/

#nav a {

width: 160px;

display: block;

padding-left:20px;

/*Width(一定要)，否则下面的Li会变形*/

}

#nav li {

background:#CCC; /*一级目录的背景色*/

border-bottom:#FFF 1px solid; /*下面的一条白边*/

float:left;

/*float：left,本不应该设置，但由于在Firefox不能正常显示

继承Nav的width,限制宽度，li自动向下延伸*/

}

#nav li a:hover{

background:#CC0000; /*一级目录onMouseOver显示的背景色*/

}

#nav a:link {

color:#666; text-decoration:none;

}

#nav a:visited {

color:#666;text-decoration:none;

}

#nav a:hover {

color:#FFF;text-decoration:none;font-weight:bold;

}

/*==================二级目录===================*/

#nav li ul {

list-style:none;

text-align:left;

}

#nav li ul li{

background: #EBEBEB; /*二级目录的背景色*/

}

#nav li ul a{

padding-left:20px;

width:160px;

/* padding-left二级目录中文字向右移动，但Width必须重新设置=(总宽度-padding-left)*/

}

/*下面是二级目录的链接样式*/

#nav li ul a:link {

color:#666; text-decoration:none;

}

#nav li ul a:visited {

color:#666;text-decoration:none;

}

#nav li ul a:hover {

color:#F3F3F3;

text-decoration:none;

font-weight:normal;

background:#CC0000;

/* 二级onmouseover的字体颜色、背景色*/

}

/*==============================*/

#nav li:hover ul {

left: auto;

}

#nav li.sfhover ul {

left: auto;

}

#content {

clear: left;

}

#nav ul.collapsed {

display: none;

}

-->

#PARENT{

width:300px;

padding-left:20px;

}

</style>

<div id="PARENT">

<ul id="nav">

<li><a
href="#Menu=ChildMenu1"
onclick="DoMenu('ChildMenu1')">我的网站</a>

<ul id="ChildMenu1"
class="collapsed">

<li><a href="#">网页教学网</a></li>

<li><a href="#">管理</a></li>

<li><a href="#">网页教学网</a></li>

<li><a href="#">管理</a></li>

<li><a href="#">网页教学网</a></li>

<li><a href="#">管理</a></li>

</ul>

</li>

<li><a
href="#Menu=ChildMenu2" onclick="DoMenu('ChildMenu2')">我的帐务</a>

<ul id="ChildMenu2"
class="collapsed">

<li><a href="#">支付</a></li>

<li><a href="#">管理</a></li>

<li><a href="#">网上支付</a></li>

<li><a href="#">登记汇款</a></li>

<li><a href="#">在线招领</a></li>

<li><a href="#">历史帐务</a></li>

</ul>

</li>

<li><a
href="#Menu=ChildMenu3" onclick="DoMenu('ChildMenu3')">网上视频教程</a>

<ul id="ChildMenu3"
class="collapsed">

<li><a
href="#">Photoshop</a></li>

<a
href="#">Java</a></li>

<li><a
href="#">Asp</a></li>

<li><a
href="#">Javascript</a></li>

</ul>

</li>

<li><a
href="#Menu=ChildMenu4" onclick="DoMenu('ChildMenu4')">在线课程</a>

<ul id="ChildMenu4"
class="collapsed">

<li><a href="#">C语言</a></li>

<a href="#">JAVA语言</a></li>

<li><a
href="#">SQL</a></li>

<li><a
href="#">C#</a></li>

<li><a
href="#">VB</a></li>

</ul>

</li>

</ul>

</div>

<script type=text/javascript><!--

var LastLeftID = "";

function menuFix() {

var obj =
document.getElementById("nav").getElementsByTagName("li");

for (var i=0; i<obj.length; i++) {

obj[i].onmouseover=function() {

this.className+=(this.className.length>0? " ": "") +
"sfhover";

}

obj[i].onMouseDown=function() {

this.className+=(this.className.length>0? " ": "") +
"sfhover";

}

obj[i].onMouseUp=function() {

this.className+=(this.className.length>0? " ": "") +
"sfhover";

}

obj[i].onmouseout=function() {

this.className=this.className.replace(new
RegExp("( ?|^)sfhover//b"), "");

}

}

}

function DoMenu(emid)

{

var obj = document.getElementById(emid);

obj.className =
(obj.className.toLowerCase() ==
"expanded"?"collapsed":"expanded");

if((LastLeftID!="")&&(emid!=LastLeftID))
//关闭上一个Menu

{

document.getElementById(LastLeftID).className = "collapsed";

}

LastLeftID = emid;

}

function GetMenuID()

{

var MenuID="";

var _paramStr = new
String(window.location.href);

var _sharpPos =
_paramStr.indexOf("#");

if (_sharpPos >= 0 && _sharpPos
< _paramStr.length - 1)

{

_paramStr = _paramStr.substring(_sharpPos
+ 1, _paramStr.length);

}

else

{

_paramStr = "";

}

if (_paramStr.length > 0)

{

var _paramArr =
_paramStr.split("&");

if (_paramArr.length>0)

{

var _paramKeyVal =
_paramArr[0].split("=");

if (_paramKeyVal.length>0)

{

MenuID = _paramKeyVal[1];

}

}

/*

if (_paramArr.length>0)

{

var _arr = new
Array(_paramArr.length);

}

//取所有#后面的，菜单只需用到Menu

//for (var i = 0; i < _paramArr.length;
i++)

{

var _paramKeyVal =
_paramArr[i].split('=');

if (_paramKeyVal.length>0)

{

_arr[_paramKeyVal[0]] =
_paramKeyVal[1];

}

}

*/

}

if(MenuID!="")

{

DoMenu(MenuID)

}

}

GetMenuID(); //*这两个function的顺序要注意一下，不然在Firefox里GetMenuID()不起效果

menuFix();

--></script>