Don't use the browser name for capability detection.

I'd like to emphasize that. For example Google Groups won't let me upload an image to my profile, because I'm not running Firefox or Internet Exploder.

Well, I tried both Epiphany (which has a very clean and fast UI, unlike Firefox which is totally cluttered) and Iceweasel (which is Firefox, but with the trademark replaced). Both are using Gecko, Gecko/20070324 for Epiphany and Gecko/20070310 for Iceweasel. So I'm very sure they have the same capabilites as Firefox 2 when it comes to web sites.

If you want to test for Firefox's capabilities, use the Gecko version number.. Thank you.

[Update: it was suggested I point people to GeckoIsGecko.org, which has links on how to properly detect the Gecko engine, instead of relying on the browser name.]

[Update: Mike Hommey pointed out that the 'Gecko/date' string is mostly meaningless, and largely is the build date; it doesn't contain tree information. Instead you should be using the "rv: 1.8.0.11" part of the User-Agent. This is also what the getGeckoRv function on the howto linked from GeckoIsGecko.org does. Oh, and Firefox 2 is not gecko 2, but IIRC uses gecko 1.8.x, just like my Epiphany.]