如图
求解决方案啊viewport我试了下还是不行
完整代码：
<!DOCTYPE html><html><head> <meta charset="utf-8"> <title>MyWeb - Using Bootstrap</title> <link rel="stylesheet" href="bootstrap/css/bootstrap.css"> <meta name="viewport" content="width=device-width, height=device-height, initial-scale=1.0"> <style type="text/css"> .panel{ transition: box-shadow 0.8s; -moz-transition: box-shadow 0.8s; /* Firefox 4 */ -webkit-transition: box-shadow 0.8s; /* Safari 和 Chrome */ -o-transition: box-shadow 0.8s; padding: 20px; border: 5px solid #ccc; filter: alpha(opacity=70); -moz-opacity: 0.7; opacity: 0.70; } .panel:hover{ box-shadow: 0px 0px 25px #5bc0de; } body{ background-image: url(bg.jpg); background-size: cover; -webkit-background-size: cover; -moz-background-size: cover; -o-background-size: cover; background-repeat: no-repeat; } .footer{ position: absolute; left: 12%; top: 90%; } </style><!-- <!?-[if lt IE 9]> <script src="http://html5shiv.googlecode.com/svn/trunk/html5.js"></script> <![endif]?->--></head><body> <script src="bootstrap/js/jquery-2.1.3.min.js"></script> <script src="bootstrap/js/bootstrap.js"></script> <div class="container"> <h1>MyWeb - Using Bootstrap</h1> <br /> <div class="panel col-xs-3"> <form> <div class="form-group"> <label for="username">用户名</label> <input type="text" class="form-control" id="username" placeholder="手机号/邮箱"> </label> </div> <div class="form-group"> <label for="password">密码</label> <input type="password" class="form-control" id="password" placeholder=""> </label> </div> <div class="checkbox"> <label> <input type="checkbox"> 自动登录 </label> <a style="float: right;" href="http://urlikesunshine.com">忘记密码</a> </div> <div align="center"> <button type="submit" class="btn btn-default">登录</button> </div> </form> </div> <div class="footer"><strong>版权所有 Sunshine 2015</strong></div> </div></body></html>
bootstrap不是很懂，不过去掉“col-xs-3”这个类，整体布局就OK了。
