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>按钮</h2>
	<p> .btn-default 类是默认/标准按钮样式:</p>
	<button type="button" class="btn btn-default">默认</button>
</div>
	
</body>
</html>
源代码

动行结果
