In the modern world of software development it's a rare day when a release actually comes out ahead of schedule. But that's the case with Mozilla's Firefox 3 Beta 2 release, which came out this morning some three days ahead of schedule.

In the latest version, Mozilla developers have improved security and performance as well as functionality. In total, Mozilla boasts in its release notes that some 900 improvements were made in Beta 2 over the Beta 1 release, which came out about a month ago.

Many improvements are focused on how Firefox handles memory. Firefox developer Mike Beltzner claimed in a mailing list posting of over 330 memory leak fixes. Memory handling and leakage issues have been a high priority item for Mozilla developers throughout the Firefox 3 process.

Firefox 3 Beta 2 also fixes leaks in how the browser handles JSON (define) (JavaScript Object Notation) cross site requests, making the browser more secure. JSON is often used in Ajax web development and is an alternative to XML over HTTP (XHR) Requests.

Security is further enhanced with anti-virus integration in Firefox's download manager.

Beta 2 also improves on the security of plugins by implementing a version check to identify plugins that are not secure.

Mozilla has also taken steps to further improve its Places bookmarking and history system which is a major new feature of the Firefox 3 browser. The Places system was originally intended to be part of the Firefox 2 release but wasn't ready in time. It has been part of the Firefox 3 development cycle since at least the Alpha 5 release in June. Fundamentally, Places makes it easy to create, manage and use bookmarks and history information.

The Beta 2 release is the tenth milestone release from Mozilla in the Firefox 3 browser development process. Though this release was ahead of schedule, the overall Firefox 3 browser effort is behind its original schedule which at one point had a final Firefox 3 release set for 2007.

While Mozilla's next generation browser development effort has had a very public milestone release cycle its chief competitor, Microsoft's Internet Explorer has been veiled in secrecy. Microsoft has publicly stated that they are working on Internet Explorer version 8. However except for a few comments made by Microsoft executives, details of the release and what it may include have not been forthcoming.

"You will hear a lot more from us soon on this blog and in other places," Dean Hachamovitch IE General Manager wrote in a recent blog post. "In the meantime, please don't mistake silence for inaction."