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>不同大小的按钮</h2> <button type="button" class="btn btn-primary btn-lg">大号按钮</button> <button type="button" class="btn btn-primary">默认按钮</button> <button type="button" class="btn btn-primary btn-sm">小号按钮</button> </div> </body> </html>
运行结果