Courtesy: Mashable

Mozilla has posted the first public beta of Mozilla Firefox 4.0, the brand new version of the Firefox web browser. It comes packed with performance improvements, a completely revamped UI which follows Chrome in putting tabs on top, a new addons manager, broader HTML5 support and more.

You can download Firefox 4.0b1 here right now, and check out the full list of changes in Firefox 4 here.