CSS with IE - is the -ms-filter required or not?

Question

I have been learning about IE's rather ridiculous-looking requirements for shadows, gradients, etc., and I'm running into some contradictions on this point:

Many sites suggest the following lines are necessary for a gradient/shadow combination:

filter: progid:DXImageTransform.Microsoft.gradient(startColorStr='#FFFFFF', EndColorStr='#F8F8F8') progid:DXImageTransform.Microsoft.Shadow(Strength=2, Direction=170, Color='#C6C6C6');
-ms-filter: "progid:DXImageTransform.Microsoft.gradient(startColorStr='#FFFFFF', EndColorStr='#F8F8F8') progid:DXImageTransform.Microsoft.Shadow(Strength=2, Direction=170, Color='#C6C6C6')"; }

CSS3Please.com suggests only the first filter is necessary for full compliance with IE 5.5-9, i.e. that the -ms-filter is of no use at all. Is -ms-filter needed any more or was that a temporary case in IE's development?

Answer 1

To answer your question even though I don't agree with its use, no it is not required. The "-ms-" prefix and other prefixes (such as "-moz-" and "-webkit-") are browser-specific and are usually just used while browsers are developing new properties. They leave the prefixed properties in later versions of the browser so that webpages using the prefixed property will still work, but both ways do the exact same thing.

P.S. IE 9 does support CSS3. It was released with Windows 7 SP1.