From the Vroom VROOM! dept.:
Mozilla's high-performance TraceMonkey JavaScript engine, which was first introduced in 2008, has lost a lot of its luster as competing browser vendors have stepped up their game to deliver superior performance. Firefox now lags behind Safari, Chrome, and Opera in common JavaScript benchmarks. In an effort to bring Firefox back to the front of the pack, Mozilla is building a new JavaScript engine called JägerMonkey.

The secret sauce that will drive Mozilla's new JavaScript engine engine into the fast lane is some code borrowed from Apple's WebKit project. Mozilla intends to bring together the powerful optimization techniques of TraceMonkey and the extremely efficient native code generator of Apple's JSCore engine. The mashup will likely deliver a significant boost in Firefox's JavaScript execution speed, making Mozilla's browser a formidable contender in the ongoing JavaScript speed race.

arstechnica.com