<html>
<head>
<title>Bootstrap 实例 - 按钮上拉菜单</title>
<link href="https://libs.baidu.com/bootstrap/3.0.3/css/bootstrap.min.css" rel="stylesheet">
<script src="https://libs.baidu.com/jquery/2.0.0/jquery.min.js"></script>
<script src="https://libs.baidu.com/bootstrap/3.0.3/js/bootstrap.min.js"></script>
</head>
<body>
<div class="row" style="margin-left:50px; margin-top:200px">
<div class="btn-group dropup">
<button type="button" class="btn btn-default dropdown-toggle" data-toggle="dropdown">
默认 <span class="caret"></span>
</button>
<ul class="dropdown-menu" role="menu">
<li><a href="#">功能</a></li>
<li><a href="#">另一个功能</a></li>
<li><a href="#">其他</a></li>
<li class="divider">
<li><a href="#">分离的链接</a></li>
</ul>
</div>
<div class="btn-group dropup">
<button type="button" class="btn btn-primary dropdown-toggle" data-toggle="dropdown">
原始 <span class="caret"></span>
</button>
<ul class="dropdown-menu" role="menu">
<li><a href="#">功能</a></li>
<li><a href="#">另一个功能</a></li>
<li><a href="#">其他</a></li>
<li class="divider">
<li><a href="#">分离的链接</a></li>
</ul>
</div>
</div>
</body>
</html>