In the wake of the release last week of Google's Chrome browser, Mozilla has released the second alpha version of Firefox 3.1.

The new build adds support for HTML 5 video, the ability to drag and drop tabs between different windows and better integration with Microsoft's Aero interface that is found in Vista.

"The second developer milestone of the next release of Firefox, codenamed Shiretoko Alpha 2, is now available for download," said Mozilla on its developer blog.

"Shiretoko is built on a pre-release version of the Gecko 1.9.1 platform, which forms the core of rich internet applications such as Firefox."

The Tracemonkey JavaScript engine, which is being built to take on Chrome's V8, has been left out of the build as it is currently being updated. It is available as an individual download.

It now seems likely that the browser will go to beta code by the end of the month and a final candidate release could be complete by October at the earliest.