Mozilla Tuesday released the latest beta of Firefox 3, including some 900 bug fixes and highlighting for users that it is for testing purposes only.

The release comes less than a week after Microsoft showed off the next version of its browser -- Internet Explorer 8 -- at its annual Mix show for developers.
Firefox 3 Beta 4 is also being targeted at developers and testers. Mozilla said the final version is expected to be released in the first part of this year although a date has not been set.

Mozilla wrote in its release notes that Firefox 3 Beta 4 includes more than 900 enhancements over the Beta 3 release, including performance and memory usage improvements, new user interface tweaks, platform enhancements and stability fixes.

On the security front, Mozilla has added malware protection to warn users about Trojans, viruses or spyware that a Web site may try to install. It also blocks known forgery sites, add-ons to ensure updates are done securely and antivirus integration. The software also integrates with parental controls that are part of Microsoft's Vista operating system.
In addition, password management has been made easier, the download manager has been improved and users can now save Tabs.

On the performance side, Mozilla has tweaked its JavaScript engine that makes Web-based applications run faster, improved memory usage and eased the fear of data loss by creating a secure database to store a user's bookmarks, history, cookies and preferences.

The beta code, however, is not without its flaws and that is why Mike Beltzner, a Mozilla Firefox developer, warned on the mozilla.dev.planning Web site that the software is only for testing.
The known issues include the fact that Windows Live Mail does not work and that users running Ubuntu Linux 7.10 may need to update their certificate databases in order to submit crash reports.