Google Chrome is a web browser developed by Google that uses the WebKit layout engine. It was first released as a beta version for Microsoft Windows in September 2008. Chrome passed 10% worldwide usage share of web browsers in January 2011. Internet Explorer is a graphical web browser developed by Microsoft and included in Windows operating systems starting in 1995. It was first included as an add-on for Windows 95. Safari is a graphical web browser developed by Apple and included in Mac OS X. It became Apple's default browser beginning with Mac OS X v10.3 in 2003.