在线运行代码 - 菜鸟教程

<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8"> 
	<title>菜鸟教程(cainiaoplay.com)</title>
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<link rel="stylesheet" href="https://cdn.staticfile.org/twitter-bootstrap/3.3.7/css/bootstrap.min.css">
	<script src="https://cdn.staticfile.org/jquery/2.1.1/jquery.min.js"></script>
	<script src="https://cdn.staticfile.org/twitter-bootstrap/3.3.7/js/bootstrap.min.js"></script>
</head>
<body>
	
<div class="container">
	<h2>简单的折叠</h2>
	<button type="button" class="btn btn-info" data-toggle="collapse" data-target="#demo">简单的折叠</button>
	<div id="demo" class="collapse in">
		Lorem ipsum dolor sit amet, consectetur adipisicing elit,
		sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam,
		quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.
	</div>
</div>

</body>
</html>
源代码

动行结果
