body{ text-align:center; margin:0; background-image:url(https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1507892240189&di=69b352da384dd7ad36aec8e75705361d&imgtype=0&src=http%3A%2F%2Fp.yjbys.com%2Fimage%2F20161207%2F1481083539122730.jpg); background-repeat:no-repeat; background-position:center center; background-attachment:fixed; background-size:cover; } #login{ margin:0 auto; width:300px; text-align:right; } #login input{ margin:5px; }
<!DOCTYPE HTML> <html> <head> <title>QA系统</title> <link rel="stylesheet" type="text/css" href="test.css"/> </head> <body> <div id="container"> <div id="login"> <form> 公司邮箱：<input type="email" name="email" autocomplete="on" autofocus placeholder="请使用邮箱名" required/><br/> 密       码：<input type="password" name="password" required placeholder="请输入密码"/><br/> <input type="submit" value="登录"/> </form> </div> <script> var container=docment.getElementById("container"); container.style.backgroundImage="url(http://www.iteye.com/upload/logo/user/37073/648c9ed4-f54b-3f4a-ac54-905f5a483307.gif?1236833802)"; </script> </div> </body> </html>
效果截图：
