使背景图片自动适应浏览器屏幕

用chrome浏览器正常显示。以下为CSS代码：

.auto-picture
{
background-image: url(../img/login-1.png);
background-position: center 0;
background-repeat: no-repeat;
background-attachment: fixed;
background-size: cover;
-webkit-background-size: cover;
-o-background-size: cover;
-moz-background-size: cover;
-ms-background-size: cover;
}

放在<body>标签，chrome浏览器可以正常使用！