Firefox 3.5 Beta 4 Released

Mozilla foundation released public beta 4 Firefox 3.5 browser on Monday, it is available for download from This release is available for Windows, Mac OS X and Linux.

Firefox jumped from 3.1 to 3.5 with this release, Mozilla decided to go with 3.5 version number because of the significant updates done to the browser.


This beta release is available in 70 languages, and it comes with the Private Browsing mode which lets you erase the data completely after once you the browsing session to protect the privacy of users. Both Google Chrome and Internet Explorer have this feature. Firefox 3.5 beta 4 brings Gecko 1.9.1 rendering engine. Tracemonkey JavaScript engine for speed and other important features.


  • This beta is now available in 70 languages – get your local version.
  • Improved tools for controlling your private data, including a Private Browsing Mode.
  • Better performance and stability with the new TraceMonkey JavaScript engine.
  • The ability to provide Location Aware Browsing using web standards for geolocation.
  • Support for native JSON, and web worker threads.
  • Improvements to the Gecko layout engine, including speculative parsing for faster content rendering.
  • Support for new web technologies such as: HTML5 video and audio elements, downloadable fonts and other new CSS properties, JavaScript query selectors, HTML5 offline data storage for applications, and SVG transforms.

As this is a beta release and intended for developers and testers many popular addons may not work with this release. Firefox 3.5 Beta 4 release notes.