源代码：
左右布局
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 mt-3"> <h2>自定义选择菜单</h2> <p>创建自定义选择菜单可以在 select 元素上添加 .custom-select 类:</p> <form> <select name="cars" class="custom-select-sm"> <option selected>自定义选择菜单</option> <option value="Google">Google</option> <option value="Runoob">Runoob</option> <option value="Taobao">Taobao</option> </select> </form> </div> </body> </html>
运行结果