We expect to see the first beta version of Firefox 4 later this month. If you want to try out some of the changes that Mozilla plans to make to its browser today, however, you can also download the latest Mozilla Developer Preview. This new version offers support for WebM video, hardware-accelerated HTML5 video for Windows (DX9), Mac (OpenGL) and HTML5 forms. The Mozilla team also managed to vastly improve the performance of the browser. Windows users will see major interface improvements, and users on all platforms can now choose to put tabs on top, just like in Google Chrome.
Note: this is a highly experimental version and Mozilla warns that current users of Mozilla Firefox should not use this developer preview version. In our experience, Mozilla’s developer previews tend to be quite stable and usable, but you mileage may vary.
Tabs on Top
The “tabs-on-top” feature is still experimental and doesn’t come with the final user interface (go to view – toolbars – tabs on top to enable them). Currently, these tabs look just like your regular Firefox tabs, but in the final version, they will be fully integrated into the browser’s interface. This developer preview also features a new interface for managing addons and themes.
Mozilla also points out that this it the first browser with full support for parsing HTML5 according to the specification.
You can find the full release notes here and our overview of Mozilla’s plans for Firefox 4 can be found here.
Speed: Still Trails in Benchmarks – But Feels Faster than Chrome
In most benchmarks, Chrome still beats Firefox. More importantly, though, this current preview version actually feels faster than the latest developer versions of Chrome. Thanks to implementing lazy frame construction, the developer preview version can render complex dynamic pages faster, which is especially apparent on large newspaper websites and other complex pages.
