Windows/Mac/Linux: Mozilla today released the first beta build of Firefox 4, complete with a new look, new features, and support for more HTML5 specs. Here's a quick screenshot tour of how it's shaping up:

The big changes come in the form of an interface overhaul and some updated support for HTML5 features. In this release the new-and-improved Firefox skin is only complete for the Windows release, so Mac and Linux users, you'll have to wait a bit. The highlights from the release notes with images (our notes in italics):


On Windows Vista and Windows 7 the menu bar has been replaced with the Firefox button


You can search for and switch to already open tabs

The stop and reload buttons have been merged into a single button on Windows, Mac and Linux. Handy, since many of us have been consolidating those buttons since Firefox 3

The Bookmarks Toolbar has been replaced with a Bookmarks Button by default (you can switch it back if you'd like).


Crash protection for Windows, Linux, and Mac when there is a crash in the Adobe Flash, Apple Quicktime or Microsoft Silverlight plug-ins.

Native support for the HD HTML5 WebM

More responsive page rendering using lazy frame construction

That covers pretty much everything that stands out in Firefox 4 so far, though a couple of feature tweaks that aren't specifically highlighted in the release notes that we particularly like include:

The new add-ons manager, which loads in a tab of its own instead of a separate window.


The new page loading progress indicator you see in the screenshot below.


If you've been kicking the tires on the new Firefox 4 beta and you've got a favorite new feature—whether we mentioned it above or not—let's hear about it in the comments.

Firefox 4 Beta 1 [Mozilla]