Mozilla Releases Firefox 4 Beta

The Mozilla Foundation has released an early beta of the upcoming version 4 of Firefox, its flagship cross-platform browser for Windows, OS X, and Linux.The long-awaited release introduces a number of improvements and additions over previous versions of Firefox. Firefox 3 came out two years ago, while version 3.5 of the Web browser debuted in 2009.

HTML 5 and CSS 3, the standards that are slated to power next-generation Websites, are clearly at the forefront of Mozilla's development efforts. Firefox 4 includes extended support for many of the new features that those two technologies introduce, including the Websocket API, which enables Web-based applications to access servers using arbitrary protocols like, for example, the one used by e-mail clients.

Most interestingly, Mozilla has chosen to support HTML 5 video playback by implementing Google's WebM video codec, which, like Firefox, is open-source and (at least in theory) unencumbered by patents. The non-profit has made it clear in the past that it has no intention of supporting H.264, a competing format backed by companies like Apple and Microsoft and currently licensed under a royalty-free scheme by the MPEG-LA Consortium.

According to a fact sheet published on Firefox's Website, the new browser also includes significant performance enhancements, such as support for hardware acceleration and a technique, called "lazy frame construction," that limits the circumstances under which certain HTML operations trigger a reflowing of a web document, thus speeding up the rendering of dynamic Web pages.

On the safety and security fronts, Firefox 4 introduces support for out-of-process plugins (OOPP) on OS X for the first time. OOPP, a technique also implemented by Safari, isolates plugins from the main browser process so that they can crash without taking down Firefox with them. Mozilla has also added a new technology called Content Security Policy, which lets Web developers specify how their pages interacts with content from other domains in an effort to mitigate certain security vulnerabilities.

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