Mozilla Firefox (abbreviated officially as Fx, but also commonly as FF), is a web browser descended from the Mozilla Application Suite, managed by the Mozilla Corporation. Firefox had 17.76% of the recorded usage share of web browsers as of April 2008, making it the second-most popular browser in current use worldwide, after Internet Explorer.
Firefox uses the open source Gecko layout engine, which implements some current web standards plus a few features which are intended to anticipate likely additions to the standards.
Firefox includes tabbed browsing, a spell checker, incremental find, live bookmarking, a download manager, and an integrated search system that uses the user\'s desired search engine. Functions can be added through around 2,000 add-ons created by third-party developers; the most popular include NoScript (script blocker), FoxyTunes (controls music players), Adblock Plus (ad blocker), StumbleUpon (website discovery), DownThemAll! (download functions) and Web Developer (web tools).
Firefox runs on various versions of Microsoft Windows, Mac OS X, Linux, and many other Unix-like operating systems. Its current stable release is version 188.8.131.52, released on April 16, 2008. Firefox\'s source code is free software, released under a tri-license GPL/LGPL/MPL.