I think this is a
fair comparison and the truth (that many cannot swallow) is that Javascript is simply too slow for non-trivial computations. All these talks about Javascript finally catching up in speed to native, and now a slightly non-trivial algorithm and Javascript falls flat in its face. I got similar result to pygorex in my run, and the Javascript implementation is indeed 60X slower than native.
Now compare that to HashSum, a a Silverlight-based implementation of the SHA-1 (I verified that it generates the same result), I clocked it and it is 20X faster than the Javascript implementation, and ~3X slower than native. Try it at http://www.hashsum.com (I wrote it; Silverlight required; sorry about the ad/layout, it was an "exercise" a while back).
So HTML5/Javascript is the future, and the future does not include Flash/Silverlight. Perhaps. But this experiment shows that Javascript is clearly way too slow compared to native or plugin. You could argue that the plugin-based scenario is going out of favor. Politics, competition, distribution, etc, are all valid reasons. But "Javascript is now just as fast" isn't one, because it is not. Those who are gung-ho about how fast Javascript is needs to write their own SHA-1 implementation that beats http://www.hashsum.com ... or at least not be blown away by it.