Sunday, June 14, 2009

Internet Explorer 8 Standards Compliant ("Compatibility") Switches

Internet Explorer 8 is the most standards compliant version of IE yet. To ensure backwards compatibility with existing web pages that target IE7 (and to a lesser extent, IE6), IE8 has standards compliant and non-compliant modes. Following are three methods to select one or the other mode:
  1. Compliant mode is enabled by default for web pages on the Internet and disabled for web pages on the Intranet. [1]
  2. When in compliant mode, a GUI button is available to switch to non-compliant mode. [1,4]
  3. Force a particular mode for a given web page by inserting the meta element at the start of the head section, "before all other elements except the title element and other meta elements."[2] For compliant mode use <meta http-equiv="X-UA-Compatible" content="IE=8" /> and for non-compliant mode use <meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" /> [1,2,3]
One other note: from JavaScript, the property document.documentMode will be present and set to 8 when compliant mode is used, otherwise this property doesn't exist. [1,2]


[1] D. Esposito, "Internet Explorer 8 and Compatibility Views", Dr. Dobbs Digest, March 2009
[2] MSDN, "Defining Document Compatibility".aspx), Feb 2009
[3], D'Technology Weblog, "IE8: Standards mode and IE7 compatibility mode", Aug 27, 2008
[4] IEBlog, "Introducing Compatibility View", Aug 27, 2008