The official release of Firefox 9 has flapped its wings out and onto the Internet. The biggest change versus Firefox 8 is the addition of type interference to the JavaScript engine, which singlehandedly improves JS execution speeds by 20- to 30-percent.

It would make sense that if you're an Internet Explorer or Chrome user because of their better JavaScript performance, it might pay to check Firefox 9 out because of this improvement. JavaScript-heavy sites such as Gmail, Facebook and Google+ should see some very nice improvements.

As usual, bug and stability fixes make their way into the new and improved Firefox 9, and the Mac-based version of Firefox 9 now includes support for "two finger swipe navigation" and deeper them integration. Finally, there's additional HTML5 and CSS support, and new hooks that allow developers to query your Do Not Track status via JavaScript.

Download it for Windows, Mac or Linux.