There are at least two if not more versions of JSUnit, one here and the other here. But there is one fundamental requirement I have for any unit testing framework, and that is that it has to integrate into an automated build script. For example, suppose you're using CruiseControl. It's got an NUnit step in it; once you write up your tests, it's the matter of a few minutes' configuration to get them running as part of the build, and it's very satisfying to watch the test counts grow as more builds are done. 117 tests run, no failures. 123 tests run, no failures. 135 tests run, no failures.
So if the framework doesn't work with automated builds, it's no good to me. Do they? I'm not sure. Edward Hieatt's version seems primarily to require a browser, although he does provide a JSUnit Server which appears to be designed to work from Ant or Java, but doesn't have any particular support for Nant or ASP.Net that I could find. Jörg Schaible's version is even less able to work in Windows; starting from the download which is only provided in tar.gz format. The documentation states that it can be run from the command line; if so that's easily adaptable to an automated build, but I didn't even take the trouble to download it, suspecting that it wouldn't even run on Windows.
So I have a lot of work to do on this technique. But it seems promising!