Mozilla hopes that TraceMonkey will shift everything back as it brings native code speed to Javascript.
Mike Shaver, Mozilla's interim vice president of engineering, said that Javascript performance nearly doubles compared to Firefox 3.0, based on the Sun Spider test of Javascript performance.
This speed brings image editing and 3D graphics into Javascript's abilities, he claimed.
You can play with it on the latest developer version of the open-source Web browser, and it will appear in the next released test version, which likely will be the first beta of Firefox 3.1 which will be out at the end of the year.