Mozilla developers have made Firefox 3.1 Alpha 2 available to download. This latest alpha - codenamed Shiretok - includes support for the new video element, one of the most highly-anticipated features of HTML 5. The HTML 5 video element offers some unique capabilities that can't presently be achieved with Flash-based video players. For instance, it enables web developers to more seamlessly intersperse video with other web content, manipulate video playback with JavaScript, and access video elements directly through the document object model (DOM). Another significant feature that landed in this alpha release is support for web worker threads, a new scripting capability that allows computationally intensive JavaScript to be run in the background so that it doesn't cause the Firefox user interface to hang. This feature and the significant JavaScript performance boost brought by the new TraceMonkey engine (which is still under development isn't included in alpha 2) will give developers the ability to leverage client-side processing to create web applications of unprecedented sophistication. Other, minor features were added in alpha 2 as well, including much-improved support for dragging tabs between windows. Dragging a tab from one window to another in alpha 2 will no longer cause the page to reload. This means that users can seamlessly move tabs between windows without disrupting page state or the contents of web forms.