IE和Firefox处理透明效果的CSS

td.pop_topleft {
 background-image: url('../img/pop_dialog_top_left.png')!important;
 background-image: none;
 filter: none!important;
 filter: progid:DXImageTransform.Microsoft.AlphaImageLoader(src='http://static.xiaonei.com/img/pop_dialog_top_left.png', sizingMethod='crop');
}

td.pop_topright {
 background-image: url('../img/pop_dialog_top_right.png')!important;
 background-image: none;
 filter: none!important;
 filter: progid:DXImageTransform.Microsoft.AlphaImageLoader(src='http://static.xiaonei.com/img/pop_dialog_top_right.png', sizingMethod='crop');
}