Firefox users and those sick of wrestling with IE will be glad to know Mozilla has released its second beta build of Firefox 3.1 which introduces a host of new tweaks, general speed increases and fixes.

The most notable changes include :-

- Added a new Private Browsing Mode.
- Added functions to make it easy to clear recent history by time as well as remove all traces of a website.
- New support for web worker threads.
- The new TraceMonkey JavaScript engine is on by default for web content.
- Improvements to the Gecko layout engine, including speculative parsing for faster content rendering.
- Removed the new tab-switching behavior based on feedback from users
- Support for new web technologies such as the and elements, the W3C Geolocation API, JavaScript query selectors, CSS 2.1 and 3 properties, SVG transforms and offline applications. More information.

Several sources who've tried the latest build are reporting massive performance improvements with the TraceMonkey Javascript engine. When running the SunSpider JavaScript benchmark it seems that the results are consistently more than twice as quick when compared to Firefox 3.0.4.

To download the latest beta, head over here.