源代码 ：
点击运行
<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Bootstrap 实例 - 下拉菜单（Dropdowns）</title> <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="dropdown"> <button type="button" class="btn dropdown-toggle" id="dropdownMenu1" data-toggle="dropdown"> 主题 <span class="caret"></span> </button> <ul class="dropdown-menu" role="menu" aria-labelledby="dropdownMenu1"> <li role="presentation"> <a role="menuitem" tabindex="-1" href="#">Java</a> </li> <li role="presentation"> <a role="menuitem" tabindex="-1" href="#">数据挖掘</a> </li> <li role="presentation"> <a role="menuitem" tabindex="-1" href="#">数据通信/网络</a> </li> <li role="presentation" class="divider"></li> <li role="presentation"> <a role="menuitem" tabindex="-1" href="#">分离的链接</a> </li> </ul> </div> </body> </html>
运行结果