Css has a very useful property called Opacity, which basically is a measure of transparency of an element.

All modern browsers Yes yes even IE has support for it.

In most browsers the value is between 0 minimum [transparent] i.e not visible to 1 maximum [opaque] i.e. completely visible

In IE the value is between 0 and 100 ,don't ask why they just like to make us unhappy.

Here I present a helper css class which will work in all browsers.

.transparent {
/* IE 5-7 */
filter: alpha(opacity=50);

/* IE 8 */
-ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=50)";

/* FF/Netscape */
-moz-opacity: 0.5;

/* Safari 1.x */
-khtml-opacity: 0.5;

/* Good browsers  (aka chrome ;) ) */
opacity: 0.5;
}

I hope you find this use full