Set Opacity in IE5.5 - IE8

Below this code works in IE 5.5 to IE 7. You set the opacity of by changing the end number which can range from 100 to 0.

element{
filter: progid:DXImageTransform.Microsoft.Alpha(Opacity=80);
}

OR

element{
filter: alpha(opacity=80);
}

Below this code works in IE 8.

element{
-ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=80)";
}