Internet Explorer doctype behaviour

Some brief tests on what compatibility mode Internet Explorer uses for various doctypes, focusing on how it's different from others.

Conclusion: The behaviour Internet Explorer 7 and 8b1 seems to follow is that only an XML declaraion is allowed above the doctype, otherwise it will use quirks mode.

NB: There is a fuller list of doctype behaviours at: hsivonen.iki.fi.

Doctype Moz IE6 IE7 IE8b1
HTML 4.01 Trans (No URL) Quirks Quirks Quirks Quirks
HTML 4.01 Trans Standards Standards Standards Standards
HTML 4.01 Strict Standards Standards Standards Standards
XHTML 1.0 Strict Standards Standards Standards Standards
XHTML + XML declaration Standards Quirks Standards Standards
XHTML + blank lines above Standards (not yet tested) (not yet tested) Standards
XHTML + comment below Standards Standards Standards Standards
XHTML + comment above Standards Quirks Quirks Quirks
XHTML + XML declaration
+ comment above
Standards Quirks Quirks Quirks
XHTML + XML declaration
+ comment below
Standards Quirks Quirks Quirks
HTML5 Standards (not yet tested) Standards Standards