<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://apps.bdimg.com/libs/bootstrap/3.3.0/css/bootstrap.min.css">
<script src="https://libs.baidu.com/jquery/2.1.4/jquery.min.js"></script>
<script src="https://apps.bdimg.com/libs/bootstrap/3.3.0/js/bootstrap.min.js"></script>
</head>
<body>
<div class="container">
<h2>Collapsible Panel</h2>
<p>Click on the collapsible panel to open and close it.</p>
<div class="panel-group">
<div class="panel panel-default">
<div class="panel-heading">
<h4 class="panel-title">
<a data-toggle="collapse" href="#collapse1">Collapsible panel</a>
</h4>
</div>
<div id="collapse1" class="panel-collapse collapse">
<div class="panel-body">Panel Body</div>
<div class="panel-footer">Panel Footer</div>
</div>
</div>
</div>
</div>
</body>
</html>