Mozilla has made the beta version of its latest web browser, Firefox 4, available online.

Firefox 4 Beta features a new interface, taking cues from Google Chrome and other browsers by placing the tabs on top by default (in Windows only; it'll come to Mac OS and Linux later on), and hiding the menu bar (instead, a new Firefox button provides access to commonly used commands).

Like other new browsers, Firefox 4 Beta provides some crash protection features: if a browser plug-in crashes, it'll just bring down the plug-in instead of causing the entire browser to crash.

Firefox 4 Beta also features bolstered HTML5 support, adds full WebGL support for 3D rendering within the browser (though it's disabled by default at this time), and adds support for Google's new WebM video format.

Firefox 4 can be downloaded for free from Mozilla's dedicated web page.