Mozilla released the second beta for its Firefox 3.1 Web browser to testers Monday. The latest release comes just seven weeks after the open source software maker launched the first beta of the version currently in the works.

“It’s not even been six months since we released Firefox 3 but what we’ve noticed is that the Web continues to move really, really quickly, and so do we. So, even before the release of Firefox 3, we’d already been working on what will become the next release of Firefox and when we took stock a couple of months after the release, we realized that we’ve done a couple of really, really impressive and incredible things,” said Mike Beltzner, director of Firefox development.

While Firefox 3 featured a dramatic speed improvement over Firefox 2, Firefox 3.1 will have the same sort of step up, Beltzner told LinuxInsider.

“We’re going to be shipping a new Javascript engine called ‘TraceMonkey’ that’s going to really improve the performance of the browser, especially for Web applications, but overall throughout the Web you should start feeling once again a browser even faster than Firefox 3. The idea was instead of waiting for a long release cycle we’d make sure we got some of these improvements into the hands of users as soon as possible,” he continued.

Beta Files

Available in 54 languages, Firefox 3.1 beta 2 includes both major and incremental changes, according to Beltzner.

Among the significant advancements are a “Private Browsing Mode” that enables users to surf the Net without leaving a trail of telltale URLs and histories.

“[It] has a more granular set of history deletion tools. It used to be that if you wanted to clear the history of your browser it was an all-or-nothing affair. Now you can say, ‘You know what, just erase the last couple hours of browsing history,’ or even ‘I want all traces of this particular Web site erased,'” Bletzner explained.

In addition to the TraceMonkey Javascript engine, Mozilla has included a few other enhancements.

Web Worker Threads is a technology layer improvement that will allow developers to move some of the heavy processing of their sites away from the browser itself so that it has less of an impact on browser performance. Downloadable fonts will enable Web site authors to specify which font they want to appear on their page, Bletzner said.

“Hopefully, we’ll start seeing more interesting and pleasant fonts than the ones your computer shipped with while browsing the Web,” he noted.

Incremental changes include improved Web rendering support, added support for Acid3 and CSS (cascading style sheets) properties, and also finished up support for technologies included in Firefox 3, such as the HTML 5 offline specifications.

The new tab-switching and preview behavior previewed in the previous beta was removed due to beta 1 tester feedback.

Firefox vs. Internet Explorer

The latest beta looks like it has good additions, especially the continued evolution to TraceMonkey, Jeffrey Hammond, a Forrester Research analyst, told LinuxInsider.

“As JavaScript becomes a more and more critical part of engaging Web sites, JavaScript performance become an important consideration. It’s one of the hottest areas of competition between Firefox, Internet Explorer, Safari and Chrome,” he continued.

That said, however, the question is how will Firefox stack up against Microsoft’s upcoming Internet Explorer 8.

“I think the private browsing matches up with the InPrivate capabilities of IE 8 fairly well, and both are moving toward partial support of HTML 5. That said, Microsoft is making some pretty substantial investments in group policy specification and community-driven rendering features to deal with the IE 7 vs. IE 8 standards view,” said Hammond.

“We’ve been seeing Firefox at about 20 percent usage rates in enterprise IT, up from 12 percent a year ago. I think that while there’s no reason this trend can’t continue, as Microsoft commits substantial resources back into the IE space, it will increasingly become harder to convert existing IE users as long as Microsoft is showing it can innovate around features and performance as well,” he concluded.