css阴影效果

.posttb{
          display:block;
          filter: progid:DXImageTransform.Microsoft.Shadow(color=#999999,direction=135,strength=3);
          border-bottom:#E3E3E3 1px solid;
          border-top:#E3E3E3 1px solid;
          BORDER-RIGHT: #E3E3E3 1px solid;
          BORDER-LEFT: #E3E3E3 1px solid;
          background-color:#ffffff;
          padding: 0px 0px 0px 0px;
          text-align:left;
          Height:300px;
          width:320px;
}