css怎么设置全屏背景图片

body、html设置

html,body{
    height: 100%;
}

图片所在div设置

.wrapper{
    background:#000000 url("../../img/login/login.jpg");
    background-attachment: fixed;
    background-repeat: no-repeat;
    background-position: center center;
    background-size: cover;
    overflow: hidden;
}