CSS背景圖拉伸自適應尺寸，全瀏覽器兼容

.bg{
background:url(http://wyz.67ge.com/wp-content/uploads/qzlogo.jpg);
filter:"progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod='scale')";
-moz-background-size:100% 100%;
    background-size:100% 100%;
background-attachment: fixed;
}