.transparent {

/* works for IE 5+. */
filter:alpha(opacity=80);

/* works for IE 8. */
-ms-filter:"progid:DXImageTransform.Microsoft.Alpha(Opacity=80)";

/* works for old school versions of the Mozilla browsers like Netscape Navigator. */
-moz-opacity:0.8;

/* This is for old versions of Safari (1.x) with KHTML rendering engine */
-khtml-opacity: 0.8;

/* This is the "most important" one because it's the current standard in CSS. This will work in most versions of Firefox, Safari, and Opera. */
opacity: 0.8;
}