I've been waiting to blog about this for a long time now. A fantastic new improvement to Mozilla's JavaScript engine (SpiderMonkey) has landed. Code-named TraceMonkey this engine utilizes a techniques, called trace trees (PDF), which adds just-in-time native code compilation to SpiderMonkey.

A major goal of the project has been to set JavaScript up to compete with natively-compiled code, rather than simply against other interpreters. This means that we're starting to see speeds that are completely out of this league when it comes to performance.