Mozilla Lights JavaScript Fire Under Firefox 18

Mozilla on Tuesday shipped its newest browser, Firefox 18, which sports a revamped JavaScript engine and support for Macs with Apple's higher-resolution Retina displays. The open-source developer also patched 28 security vulnerabilities, more than two-thirds of them marked critical, Mozilla's highest threat rating, and revoked digital certificates that were initially thought to be in the hands of cyber criminals.

At the top of Firefox 18's new feature list, however, was "IonMonkey," a new JavaScript JIT (just-in-time) compiler that renders complex JavaScript - like that used by Web-based games or apps - significantly faster than earlier engines. Depending on the performance benchmark, IonMonkey speeds up Firefox's JavaScript rendering as much as 25%, Mozilla claimed. That number was at the high end of a 7% to 26% speed-improvement range that the JIT compiler team cited last September when IonMonkey debuted in Firefox 18's "Nightlies," or roughest, build.