Mozilla releases first Firefox 4 beta

The Mozilla development team have announced the arrival of the first beta for version 4.0 of their Firefox web browser. According to Firefox development director Mike Beltzner, this beta is aimed at providing "an early look at what’s planned" for the browser update. Firefox 4 will be the next major release of Mozilla's popular open source browser and will include a number of improvements, updates and new features.

Firefox 4 Beta 1 is based on version 2.0 of the Gecko rendering platform – the Firefox 3.6 branch uses Gecko 1.9.2 – and features a new Add-ons Manager and extension management API, and a number of Windows only changes, such as a new default 'tabs on top' layout for Windows systems. Mac OS X and Linux systems will receive the new tabs on top layout in a future update "when the theme has been modified to support the change". Other Windows improvements include a new Firefox Button on Vista and Windows 7 systems, replacing the menu bar, and an experimental Direct2D rendering back end – currently disabled by default.

Firefox 4 on Windows features a new menu and a "Smart Location Bar". Other changes include API improvements for JS-ctypes, a new HTML5 parser, more responsive page rendering, support for additional HTML5 form controls and partial support for CSS Transitions. User interface (UI) updates include a new default Bookmarks Button that replaces the Bookmarks Toolbar and a new single button for stop and reload. Native support for the HD HTML5 WebM / VP8 video format and full support for WebGL – a JavaScript binding to OpenGL ES 2.0 with industry support from Google, Mozilla and Opera – (currently disabled by default) have also been added.

Originally introduced in Firefox 3.6.4, version 4.0 includes enhanced crash protection technology from the Mozilla Lorentz Project, aimed at bringing full process isolation to Firefox, separating web pages and plug-ins from the main browser by running them in their own processes. Crash protection is now supported on Windows, Mac OS X and Linux, and currently protects the browser against crashes in the Adobe Flash, Apple QuickTime or Microsoft Silverlight plug-ins.

Beltzner notes that the developers plan to release a new beta version "every two to three weeks". A first release candidate (RC) for Firefox 4 is currently scheduled to arrive in October of this year. A final release date, however, has yet to be confirmed.

Although the developers consider this release to be "stable and safe to use for daily web browsing", use in production environments and on mission critical systems is not advised. Users testing the release are encouraged to provide feedback and report any bugs that they encounter.

More details about the release, including a list of known issues, can be found in the release notes and in the official release announcement by Beltzner. Firefox 4.0 Beta 1 is available to download for Windows, Mac OS X and Linux. The latest stable release of Firefox is version 3.6.6 from the end of June.

Firefox binaries are released under the Mozilla Firefox End-User Software License Agreement and the source code is released under disjunctive tri-licensing that includes the Mozilla Public Licence, GPLv2 and LGPLv2.1.

See also:

• Firefox to become IBM's new default browser, a report from The H.
• Mozilla releases Firefox 3.6.6, a report from The H.
• Mozilla's Beltzner announces Firefox 4 plans, a report from The H.

(crve)