xxxxxxxxxx<html> <head> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <link rel="stylesheet" href="//cdn.bootcss.com/bootstrap/3.3.6/css/bootstrap.min.css"> <script src="//cdn.bootcss.com/jquery/2.1.1/jquery.min.js"></script> <script src="//cdn.bootcss.com/bootstrap/3.3.6/js/bootstrap.min.js"></script> </head> <body> <div class="container"> <h2>实例</h2> <div class="center-block" style="width:150px;background-color:#ccc;">该 div 显示在中间</div> </div> </body></html>