<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>Hello World</title> <link href="//netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css" rel="stylesheet"> </head> <body> <nav class="navbar navbar-default" role="navigation"> <div> <!-- Brand and toggle get grouped for better mobile display --> <div> <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1"> <span>Toggle navigation</span> <span></span> <span></span> <span></span> </button> <a href="#">某管理系统</a> </div> <!-- Collect the nav links, forms, and other content for toggling --> <div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1"> <ul class="nav navbar-nav"> <li><a href="#">首页</a></li> <li class="dropdown active"> <a href="#" data-toggle="dropdown">功能<span></span></a> <ul role="menu" aria-labelledby="dropdownMenu1"> <li role="presentation"><a role="menuitem" tabindex="-1" href="#">Action</a></li> <li role="presentation"><a role="menuitem" tabindex="-1" href="#">Another action</a></li> <li role="presentation"><a role="menuitem" tabindex="-1" href="#">Something else here</a></li> <li role="presentation"><a role="menuitem" tabindex="-1" href="#">Separated link</a></li> </ul> </li> <li><a href="#">帮助</a></li> </ul> <form class="navbar-form navbar-left" role="search"> <div> <input type="text" placeholder="用户名..."> </div> <div> <input type="password" placeholder="密码..."> </div> <button type="submit" class="btn btn-default">登录</button> </form> </div><!-- /.navbar-collapse --> </div><!-- /.container-fluid --> </nav> <script src="http://cdn.bootcss.com/jquery/1.11.1/jquery.min.js"></script> <script src="http://cdn.bootcss.com/bootstrap/3.2.0/js/bootstrap.min.js"></script> </body> </html>
下拉菜单要加class="dropdown-menu"