After my email (which follows) had been submitted,Woops.

I want to make www.neilmix.com/2007/02/07/threading-in-javascript-17/ fail fast for other browsers (than FF2+), but this:outputs this in Firefox 2.0.0.6:with no mention of "2". Or am I not asking for the correct thing? Thanks!
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I can't remember off the top of my head how to get the version number. That's because the primary purpose of the script is to get actual funcionality, not the cosmetic version numbers.

For that functionality, the gecko rv version is the actual thing you test for, in this case, gecko rv 1.8 is the gecko engine. This bypasses all the different flavors of gecko powered browsers and ids, like firefox, iceweasel in debian, epiphany, and so on.

You can check out the mozilla specific return values, look in the computer information script on the browser detection page for an example of how to do that.

But remember, comparing numbers like 2.0.0.6 with other numbers is very unreliable and prone to failue due to differences in versioning numbers of different firefox/gecko flavors.
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OK, thanks. Would you happen to know the earliest supporting Gecko version?
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From what I can remember, the first gecko was, I think, 0.6

Then 0.9 was Netscape 6 with some tweaks, back when netscape and mozilla were actually technically different internally.

I think also possibly Galeon browser, based on the gecko engine, may not use the same rv system, which makes it even more painful. Happily, almost nobody uses galeon.
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You lost me. To ask it a clearer way, what's the earliest Gecko to support JavaScript 1.7?
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I found I think just what you are looking for at wikipedia

Scroll down the page until you get to 'Version correspondence', that shows precise gecko rv engine support.


however, you'll notice that:

As you see, 1.7 support was added in a subversion of 1.8, 1.8.1

Which means you have to do more scripting to handle precise detections.

However, in my opinion, this is always a bad method to use. FAR BETTER is to find a javascript method or function that you need to have support for, then to implement an inititlal test of that method, with an alternate option for browsers that do not support that method.

This is how I always handled netscape 4 things in the past, I would wrap all my stuff up in conditionals:



So all you need to do is find a single javascript/ecmascript 1.7 specific method or feature, test for that, and then escape if not supported, and i you also need to make sure it's a gecko browser, simply test for gecko support as well, like: if ( some.method && isGecko ).....
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Hmm... <script type="application/javascript;version=1.7"> isn't recognized in Opera/IE6, so I can set a variable inside it and detect support by that variable. Thanks!
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