css图片置灰

.transp { /* make the div translucent */

   opacity: 0.6;                /* Firefox, Safari(WebKit), Opera)

   filter: "alpha(opacity=60)"; /* IE 8 */

   filter: alpha(opacity=60);   /* IE 4-7 */

   zoom: 1;                     /* needed in IE up to version 7, or set width or height to trigger "hasLayout" */ 

}