Mozilla on Thursday released the third beta version of Firefox 3.1, aka Shiretoko, one of the frontrunners in the current race to improve Web browsers with competition hotting up from safari, chrome etc.

“As recently proposed, the version number of the Shiretoko project will be changed to Firefox 3.5 before the upcoming fourth beta release,” said Mike Beltzner, Mozilla’s director of Firefox, in a brief entry on the company’s developer blog.

As per Cnet , Firefox is vying with Apple’s Safari 4 beta and Google’s Chrome for the best JavaScript performance, a factor that’s important for the new generation of sophisticated Web sites such as Google Docs and or Facebook applications. So far, Internet Explorer has the dominant market share, with Firefox in second place.

Here’s Mozilla’s full list of improvements in the new beta:

• 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.

You can  download Firefox 3.1 beta 3 here.Download firefox-31