1、在登陆页经常有张背景图片。
<body>
</body>
<style>
body {
background: url(http://static.ixuezhong.cn/uploadimg/admin/20190522/9e5f80182ca84201bcd6ac190743d004.png) center center / cover no-repeat fixed;
}
</style>
分开写：
background-image: url(http://static.ixuezhong.cn/uploadimg/admin/20190522/9e5f80182ca84201bcd6ac190743d004.png);
background-size: cover;
background-position: center center;
background-repeat: no-repeat;
background-attachment:fixed; /**图片不跟随浏览器滑动而移动**/
结果：
