源代码 ：
点击运行
<!DOCTYPE html> <html> <head> <title>Bootstrap 实例</title> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <link rel="stylesheet" href="https://cdn.staticfile.org/twitter-bootstrap/4.3.1/css/bootstrap.min.css"> <script src="https://cdn.staticfile.org/jquery/3.2.1/jquery.min.js"></script> <script src="https://cdn.staticfile.org/popper.js/1.15.0/umd/popper.min.js"></script> <script src="https://cdn.staticfile.org/twitter-bootstrap/4.3.1/js/bootstrap.min.js"></script> </head> <body> <div class="container"> <h2>简单的折叠</h2> <p>点击按钮内容会再显示与隐藏之间切换。</p> <button type="button" class="btn btn-primary" data-toggle="collapse" data-target="#demo">简单的折叠</button> <div id="demo" class="collapse"> 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>
运行结果