Instead, programmers are expected to write their code in some other language – such as C or C++ – and then compile their source into code for execution in the browser using tools like Emscripten.
Because code is still 100 per cent valid Java Script, it will run in any modern browser.
But with Odin Monkey's special optimizations enabled, Mozilla claims Firefox can execute code with performance only about twice as slow as the equivalent native code – which is saying something, for a Java Script engine – and it plans to do even better in future.
The main downside to is that its syntax is so sparse and its coding standards are so strict that it's not very human-friendly.
The Mozilla Foundation has shipped Firefox 22 to the release channel, bringing with it improved support for web-based real-time communications and a significant performance boost for some Java Script applications, among other features.
The new version comes with support for the nascent Web RTC API enabled by default for the first time.
Technically still a work in progress at the Worldwide Web Consortium (W3C), Web RTC is a proposed standard that enables browser-based voice calling, video chat, and peer-to-peer data sharing.
Other than Firefox 22, only the latest versions of Chrome OS and the desktop Chrome browser support Web RTC so far, but other browsers are expected to incorporate it as the standard matures.
In February, Google and Mozilla showed off a cross-browser video chat session between a beta version of Chrome and a nightly build of Firefox.
As of Tuesday, those same capabilities are available in the stable branch of the Firefox browser.