Mozilla announced the availability of the first Firefox 3.6 beta last week. Firefox 3.6, codenamed Namoroka, is an incremental update that introduces a handful of new features, enhanced performance, and some noteworthy improvements to Web standards support. The final version of Firefox 3.6 could be released next year.

We first looked at Firefox 3.6 in August when we tested the first alpha release. It has some excellent performance improvements under the hood that will boost JavaScript execution speed. Firefox 3.6 also brings some nice CSS enhancements, including support for some useful non-standard features like WebKit's gradients.

Several important new features have been added since the original alpha version. Mozilla recently introduced support for the Web Open Font Format (WOFF) which was developed by type designers Tal Leming and Erik van Blokland in collaboration with Mozilla. Firefox 3.6 will also expand on the work that Mozilla did with the HTML 5 video element in 3.5. Video poster frames and fullscreen playback are now supported.

Mozilla's commitment to advance mobile browsing is demonstrated in 3.6 with the introduction of a new MozOrientation event handler that makes it possible for webpages to tap into device accelerometer data through JavaScript. I saw this demonstrated on a Nokia N900 with Mozilla's Fennec browser during the recent Maemo Summit. In the demo, a dot drawn on an HTML Canvas element moved around on the screen as the device was tilted.

The Personas project, which was launched by Mozilla Labs in 2007, is now an official part of the Firefox browser. Personas are lightweight themes that allow the user to trivially skin the browser's user interface and apply custom (usually tacky) images and colors to the tabs and main toolbars. Mozilla maintains a Personas gallery online where users can go to get new visual styles.

Mozilla is encouraging add-on developers to start working on compatibility with 3.6. The organization has a very long history of proactive engagement with the third-party developer community to boost the number of add-ons that will work at launch for new versions of the browser. They have introduced a nifty new compatibility-reporting tool that will help users identify and report add-ons that aren't working properly with 3.6.

Firefox 3.6 is available for download from the Mozilla website. I was unable to get it to run on Linux (BadWindow error, typically caused by Nvidia/Xorg/Compiz issues), but I tested it extensively on Windows Vista. For additional details, see the official release announcement and the notes for developers.