背景图片自适应全屏

.g3dDIV{
    position:fixed;
    top: 0;
    left: 0;
    width:100%;
    height:100%;
    min-width: 1000px;
    z-index:-10;
    zoom: 1;
    background-color: #fff;
    background: url('/js/static/images/sceneBackground.png');
    background-repeat: no-repeat;
    background-size: cover;
    -webkit-background-size: cover;
    -o-background-size: cover;
    background-position: center 0;
}