Windows Internet Explorer 8 (abbreviated as IE8) is a web browser developed by Microsoft in the Internet Explorer browser series. The browser was released on March 19, 2009, for Windows XP, Windows Server 2003, Windows Vista, Windows Server 2008, and Windows 7. Both 32-bit and 64-bit builds are available. It is the successor to Internet Explorer 7, released in 2006, and is the default browser for Windows 7 and Windows Server 2008 R2 operating systems. As of January 2011, estimates of IE8's global market share ranged from 26 percent to 33 percent.
Internet Explorer 8 is the first version of IE to pass the Acid2 test, and the last of the major browsers to do so, although it scores only 20/100 on the Acid3 Test. According to Microsoft, security, ease of use, and improvements in RSS, Cascading Style Sheets, and Ajax support were its priorities for IE8.
Internet Explorer 8 is the last version of Internet Explorer to be supported on Windows XP; the next version, Internet Explorer 9, is supported only on Windows Vista and Windows 7 operating systems.
