Firefox 9 slinks onto the scene with fancy JavaScript optimizations

Another six weeks have gone by, and another version of Firefox has been released. Still not officially "live," Firefox 9 improves on Firefox 8 with a JavaScript engine that's up to 30 percent faster and, well, not a whole lot else. Mac OS X users will have a little more to gain, as Firefox 9 also includes two-finger gestures for backward and forward navigation on that platform.

The new version includes a number of bug fixes to improve stability and security, better support for HTML5, CSS, and MathML, and some improvements to its Do Not Track feature to allow scripts to know if tracking is enabled or not. All told, the new release includes more than one thousand bug fixes and improvements.

But if Firefox users will notice anything new in Firefox 9, it's the JavaScript engine. The updated engine is potentially a big win for Firefox. Common JavaScript benchmarks have shown performance improvements of around 30 percent, and a paper about the new technology claims that real Web sites can see performance gains of 50 percent.