Mozilla has announced the released of the Firefox 3.1 beta 3, which is the fifth development milestone and third beta release of Firefox ^[1] 3.1 to the testing community.

This version of Firefox is based on the Gecko 1.9.1 rendering platform which has been in development for last 9 months.

Major Changes in Firefox 3.1 beta 3

• This beta is now available in 64 languages – get your local version.
• Improved the new Private Browsing Mode.
• Improvements to web worker thread support.
• Improved performance and stability with the new TraceMonkey JavaScript engine.
• New native JSON support.
• Improvements to the Gecko layout engine, including speculative parsing for faster content rendering.
• Support for new web technologies such as the <video> and <audio> elements, the W3C Geolocation API, JavaScript query selectors, CSS 2.1 and 3 properties, SVG transforms and offline applications.

If you are going to download the latest beta, be sure to backup your Firefox bookmarks and settings ^[2] first, also some of your add-ons may stop working when you install this release.

Firefox 3.1 Beta 3 Release Notes ^[3]