{
/*
whichEl = eval("document.getElementById('"+"submenu" + sid+"')")
imgmenu = eval("document.getElementById('"+"imgmenu" + sid+"')")
if (whichEl.style.display == "none")
{
if (whichEl.style.display=='none') whichEl.style.display=''
else whichEl.style.display = 'none'
imgmenu.background="image/menuup.gif"
}
else
{
if (whichEl.style.display=='none') whichEl.style.display=''
else whichEl.style.display = 'none'
imgmenu.background="image/menudown.gif"
}
*/
//某一分类弹开,其它分类自动关闭
whichEl = eval("document.getElementById('"+"submenu" + sid+"')")
imgmenu = eval("document.getElementById('"+"imgmenu" + sid+"')")
var newsTD=document.getElementsByTagName("td")
var obj=whichEl
if(obj.style.display=="none")
{
for(i=8i<newsTD.lengthi++)
{
if(newsTD[i].id.indexOf("submenu")!=-1)
{
if (newsTD[i].style.display!="none")
{
newsTD[i].style.display = "none"
}
}
if(newsTD[i].id.indexOf("imgmenu")!=-1)
{
newsTD[i].background = "image/menudown.gif"
}
}
obj.style.display=""
imgmenu.background="image/menuup.gif"
}
else if(obj.style.display!="none")
{
obj.style.display="none"
imgmenu.background="image/menudown.gif"
}
}
</SCRIPT>
直接写了一下，不知道是不是你想要的，<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/htmlcharset=UTF-8">
<title>Insert title here</title>
<script type="text/javascript">
function clickA(){
document.form1.textname.style.display=""
document.form1.selectname.style.display="none"
}
function clickB(){
document.form1.textname.style.display="none"
document.form1.selectname.style.display=""
}
</script>
</head>
<body>
<form name="form1" action="">
<select>
<option onclick="clickA()">A</option>
<option onclick="clickB()">B</option>
</select>
<input type="text" name="textname" style="display:none" >
<select name="selectname" style="display:none">
<option>A</option>
<option>B</option>
</select>
</form>
</body>
</html>
你这个效果的下拉菜单，不需要用 JavaScript，只用CSS就能实现。
加上一句
li:hover ul{ display:block}
就行了。
<!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/htmlcharset=utf-8"/>
<title>无标题文档</title>
<style type="text/css">* {
margin: 0px
padding: 0px
}
body {
font-family: Verdana, Geneva, sans-serif
font-size: 14px
}
#nav {
width: 600px
height: 40px
background-color: #eee
margin: 0 auto
}
ul {
list-style: none
}
ul li {
float: left
line-height: 40px
text-align: center
width: 100px
}
a {
text-decoration: none
color: #000
display: block
}
a:hover {
color: #F00
background-color: #666
}
ul li ul li {
float: none
background-color: #eee
margin: 2px 0px
}
ul li ul {
display: none
}
li:hover ul{ display:block}
</style>
</head>
<body>
<div id="nav">
<ul>
<li><a href="#">首页</a></li>
<li><a href="#">课程大厅</a>
<ul>
<li><a href="#">JavaScript</a></li>
<li><a href="#">Html/CSS</a></li>
</ul>
</li>
<li><a href="#">学习中心</a>
<ul>
<li><a href="#">视频学习</a></li>
<li><a href="#">实例练习</a></li>
<li><a href="#">问与答</a></li>
</ul>
</li>
<li><a href="#">经典案例</a></li>
<li><a href="#">关于我们</a></li>
</ul>
</div>
</body>
</html>
