How can I controle the visibility level of a div and make it see through?

Question

Can I control the visibility of some div in my website and make to become see-through using CSS only? In flash it's done through controlling what is called Alfa so I'm wondering if such a thing exist in CSS!

Edition 001

Can I control the opacity of the div's background only? So the text in the div wouldn't be effected?

Answer 1

You can use opacity in CSS

.transparent_class {
 opacity: 0.5;
}

I think there are some problems with opacity in Internet Explorer so here is example how to change transparency in IE:

.opaque1 { // for all other browsers
 opacity: .5;
}

.opaque2 { // for IE5-7
 filter: alpha(opacity=50);
}

.opaque3 { // for IE8
 -ms-filter:"progid:DXImageTransform.Microsoft.Alpha(Opacity=50)";
}

HTH