<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>導航菜單</title>
<style>
*{margin:0; padding:0;}
a{font-size:12px;}
#nav{background-color:#4689f4; width:600px; height:40px; margin:0 auto;}
#nav ul{ list-style-type:none;}
#nav ul li{float:left; height:40px; line-height:40px; text-align:center; position:relative;}
#nav ul li a{ text-decoration:none; color:#fff; display:block; padding:0 30px;transition: all .5s;}
#nav ul li a:hover{color:#FFF; background-color:#4778c7;transition: all .5s;}
#nav ul li ul{ display:none; position:absolute; top:40px; left:0;}
#nav ul li ul li{float:none; background-color:#4689f4; margin-top:2px;}
#nav ul li:hover ul{display:block;}
#nav ul li ul li {height:40px;}
.header{background:#4689f4;}
</style>
</head>
<body>
<div class="header">
<div id="nav">
<ul>
<li><a href="#">首頁</a></li>
<li><a href="#">前端課程</a>
<ul>
<li><a href="#">Javascript</a></li>
<li><a href="#">jQrey</a></li>
<li><a href="#">PHP</a></li>
<li><a href="#">HTML5</a></li>
<li><a href="#">CSS</a></li>
</ul>
</li>
<li><a href="#">學習中心</a></li>
<li><a href="#">經典案例</a></li>
<li><a href="#">關於我們</a></li>
</ul>
</div>
</div>
</body>
</html>
效果：
