CSS3阴影（兼容IE）

.shadow {
    -moz-box-shadow: 3px 3px 4px #000;
    -webkit-box-shadow: 3px 3px 4px #000;
    box-shadow: 3px 3px 4px #000;
    /* For IE 8 use IE shadow滤镜 */
    -ms-filter: "progid:DXImageTransform.Microsoft.Shadow(Strength=4, Direction=135, Color='#000000')";
    /* For IE 5.5 - 7 IE shadow滤镜*/
    filter: progid:DXImageTransform.Microsoft.Shadow(Strength=4, Direction=135, Color='#000000');
}