<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="bootstrap-3.3.7-dist/js/bootstrap.js"></script>
<script src="bootstrap-3.3.7-dist/js/jquery-3.3.1.js"></script>
<script src="bootstrap-3.3.7-dist/js/bootstrap.min.js"></script>
</head>
<body>
<div class="dropdown">
<button class="btn btn-default dropdown-toggle" data-toggle="dropdown">
这是按钮
<span class="caret"></span>
</button>
<ul class="dropdown-menu">
<li>
<a href="http://www.baidu.com">百度</a>
</li>
<li>
<a href="http://www.baidu.com">百度</a>
</li>
<li>
<a href="http://www.baidu.com">百度</a>
</li>
</ul>
</div>
</body>
</html>
