Mozilla has released the first beta release of Firefox 3.6, the next version of the popular open-source browser. At first glance it merely seems like a performance upgrade to the current Firefox version, 3.5 that was released in June. However, when you spend some time browsing around, especially with JavaScript heavy web apps, you realize that the page load times are significantly faster. This new beta also has better support for the latest emerging web standards like HTML5 and CSS3, better native video playback, a new plugin updating mechanism and some new tab behaviors.

The performance boost in the new browser is thanks to a few tweaks to TraceMonkey, Mozilla’s own engine for rendering JavaScript on web pages. The new version of TraceMonkey has been optimized to work within Firefox, which means that will speed up Firefox UI elements written in JavaScript as well. However, as with Firefox’s previous releases, the browser still requires quite a bit of RAM. Firefox 3.6 beta still requires more RAM than Safari or Opera.

Mozilla has also tweaked the behavior of the tabs. Ctrl+click on a link or Open in a New Tab opens the tab right next to the active tab; a significant improvement from previous versions of the browser where the new tab opened at the end of the line of opened tabs. Firefox 3.6 beta also has the long awaited tab preview when switching tabs using the inbuilt tab switcher. However, this feature does not come enabled as default. Hopefully, it will be enabled when the final release is made available, sometime before the end of 2009.