Bootstrap下拉菜单默认需要通过点击，才可以打开，在管理系统的开发过程中，使用悬停代替点击能减少一步操作，更人性化。下面是实现方式：
<!DOCTYPE html> <html> <head> <link href="https://cdn.bootcss.com/bootstrap/3.3.5/css/bootstrap.min.css"> <script src="https://cdn.bootcss.com/jquery/2.1.4/jquery.js"></script> <script src="https://cdn.bootcss.com/bootstrap/3.3.5/js/bootstrap.js"></script> <script src="https://cdn.bootcss.com/bootstrap-hover-dropdown/2.0.10/bootstrap-hover-dropdown.min.js"></script> </head> <body> <div> <button type="button" data-toggle="dropdown" data-hover="dropdown"> 主题 <span></span> </button> <ul 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"></li> <li role="presentation"> <a role="menuitem" tabindex="-1" href="#">分离的链接</a> </li> </ul> </div> </body> </html>