DoctypeSwitching

[need general description of doctype switching here]

History of doctype switching in browsers

The pre-history of doctype switching begins with Todd Fahrner's posting to the mozilla-layout mailing list:

Please consider taking a modal approach: ship a browser with 2 independent rendering systems. Use the legacy system for legacy content. Use NGLayout when rendering documents authored in either HTML 4.0 Strict or XML (this will include HTML 5.0). Pay attention to the DOCTYPE.

From there, fast-forward to March 2000, when Internet Explorer 5 for the Macintosh is released, with the first implementation of doctype switching. In the same month, Mozilla adds support for it, and shortly thereafter, a subsequent Transitional DOCTYPE with URI should trigger strict layout mode bug report leads to further refinements of the switching code (in part to more closely match the behavior in IE5 for Mac).

The first release of IE for Windows to include doctype-switching support was IE6 in August 2001. Then in June 2006, Mozilla added an "almost standards" mode.

In January 2008, it was announced that IE8 would support doctype-switching through use of a <meta> tag.

See also

• Activating the Right Layout Mode Using the Doctype Declaration
• quirks mode page at Wikipedia
• Mozilla's DOCTYPE sniffing
• The Opera 9 DOCTYPE Switches
• CSS Enhancements in Internet Explorer 6: The !DOCTYPE "Switch"
• Beyond DOCTYPE: Web Standards, Forward Compatibility, and IE8
• Compatibility and IE8