<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Bootstrap 下拉菜单</title>
<link rel="stylesheet" href="http://cdn.static.runoob.com/libs/bootstrap/3.3.7/css/bootstrap.min.css">
</head>
<body>
<div class="container">
<div class="dropdown">
<button class="btn dropdown-toggle" id="dropdownMenu1" data-toggle="dropdown">
主题
<span class="caret"></span>
</button>
<ul class="dropdown-menu" role="menu" aria-labelledby="dropdownMenu1">
<li role="presentation">
<a href="" role="menuitem" tabindex="-1" >java</a>
</li>
<li role="presentation">
<a role="menuitem" tabindex="-1" href="#">数据挖掘</a>
</li>
<li role="presentation">
<a role="menuitem" tabindex="-1" href="#">数据通信/网络</a>
</li>
<li role="presentation" class="divider"></li>
<li role="presentation">
<a role="menuitem" tabindex="-1" href="#">分离的链接</a>
</li>
</ul>
</div>
</div>
<script src="http://cdn.static.runoob.com/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="http://cdn.static.runoob.com/libs/bootstrap/3.3.7/js/bootstrap.min.js"></script>
</body>
</html>