Firefox 3.1 Alpha 2, code named 'Shiretoko', will be the last in a short series of alpha editions; Mozilla has set a late-September code freeze for Beta 1, and will presumably deliver the first preview for the general public next month.
Mozilla added support for the new element to Alpha 2 and the opening round of what's called "web worker threads," enhanced the browser's performance, and enabled drag-and-drop of tabs between windows.
Support for the tag, part of the HTML 5 standard, has been pitched by developers as a way to ditch proprietary formats, including the popular Flash, and let site designers embed video directly into pages, then manipulate and control the video with scripting.
Mozilla is playing catch-up here with Apple's Safari, which already supports the tag. Other browsers, however, including Google's new Chrome and Microsoft's Internet Explorer 8 (IE8) Beta 2, have yet to offer support for the element.
Other adds and changes to Firefox 3.1 showing up for the first time include: the between-windows drag-and-drop; new support for several CSS (cascading style sheets) 2.1 and CSS 3 properties; and a performance boost when viewing images with embedded color profiles.
Firefox 3.1 has been touted as a fast-track update to June's version 3.0; that edition, for example, worked its way through eight alphas altogether.
Mozilla has declined to set a hard deadline for the browser, saying only that it is shooting for a late-2008 or early-2009 release. Last week, however, the open-source developer pushed back Firefox 3.1 Beta 1's schedule by three weeks.
Alpha 2 can be downloaded from Mozilla's site in versions for Windows, Mac OS X and Linux.