简单教程
提交运行
代码编辑器：
<!DOCTYPE htm> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <link href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet"> <style>body {margin:20px}</style> <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">只要用心为用户挖掘想要的功能，这些不谋而合的想法就会不断出现 </div> <script src="https://cdn.bootcss.com/jquery/1.12.4/jquery.js"></script> <script src="https://cdn.bootcss.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
运行结果：