Recently I came across some issues with Internet Explorers transparency. When I applied transparency to a div on one of my sites with the IE CSS it didn’t apply any transparency. There was no problems with the code, it was all correct, IE just didn’t want to apply the transparency.

The CSS I was using looks similar to this:

filter: alpha(opacity=50);

With Internet Explorer your opacity range goes from 0-100, so 50 should set the opacity to 50%. Of course it didn’t.

The Solution:

After hours of pulling out my hair, the problem was simply that the div didn’t have a width specified. The problem appears to be in all versions of Internet Explorer, even in IE8 beta. So if you’re having the same problem just specify a width for the element you are applying the transparency/opacity to and it should once again apply the transparency correctly.