用CSS做下拉列表的特效，代码如下：
<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title></title>
<style type="text/css">
* {
margin: 0px;
padding: 0px;
}
#nav {
width: 500px;
background-color: #737373;
height: 40px;
/*border-radius: 10px;*/
position: relative;
margin: 0px auto;
top: 0px;
}
.nav-container {
width: 100%;
height: 40px;
position: absolute;
}
.banner {
float: left;
text-align: center;
height: 40px;
width: 20%;
line-height: 40px;
}
.banner:hover {
background-color: #00BFFF;
cursor: pointer;
}
div ul {
list-style: none;
/*display: none;*/
background-color: blue;
overflow: hidden;
/*模拟height:auto时候的情况*/
max-height: 0px;
transition: max-height 0.3s;
/*多浏览器支持*/
-moz-transition: height 1s;
-webkit-transition: height 1s;
-o-transition: height 1s;
}
.banner:hover ul {
/*display: block;*/
width: 100%;
max-height: 160px;
}
div ul li {
overflow: hidden;
}
div ul li:hover {
background-color: red;
}
</style>
</head>
<body>
<div class="nav-container">
<div id="nav">
<div id="nav-button-1" class="banner">第1个导航
<ul>
<li>1</li>
<li>2</li>
<li>3</li>
<li>4</li>
</ul>
</div>
<div id="nav-button-2" class="banner">第2个导航
<ul>
<li>1</li>
<li>2</li>
<li>3</li>
</ul>
</div>
<div id="nav-button-3" class="banner">第3个导航
<ul>
<li>1</li>
<li>2</li>
</ul>
</div>
<div id="nav-button-4" class="banner">第4个导航
<ul>
<li>1</li>
<li>2</li>
<li>3</li>
<li>4</li>
<li>5</li>
</ul>
</div>
<div id="nav-button-5" class="banner">第5个导航
<ul>
<li>1</li>
<li>2</li>
<li>3</li>
<li>4</li>
<li>5</li>
</ul>
</div>
</div>
</div>
</body>
</html>
效果如下：
这就是做出来的样子，当然可以做成横向列表，自己试着做一下。