Re: let authors choose text/html or application/xhtml+xml (detailed review of section 1. Introduction)

Dan Connolly wrote:
> XHTML documents served as text/html result in interoperable behavior
> in typical cases, so that constraint is too strong. Please change
> it to "SHOULD be sent..." and "SHOULD NOT be served...".

Several typical cases result in non-interoperable behaviour in current 
browsers - e.g. <script src="..."/> acts inconsistently when parsed as 
text/html:

http://software.hixie.ch/utilities/js/live-dom-viewer/?%3Chtml%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1999%2Fxhtml%22%3E%0D%0A%3Chead%3E%0D%0A%3Ctitle%3E%26lt%3Bscript%2F%26gt%3B%20in%20XHTML-as-text%2Fhtml%3C%2Ftitle%3E%0D%0A%3Cscript%20type%3D%22text%2Fjavascript%22%20src%3D%22emptyfile.js%22%2F%3E%0D%0A%3C%2Fhead%3E%0D%0A%3Cbody%3E%0D%0A%3Cp%3EBody%3C%2Fp%3E%0D%0A%3C%2Fbody%3E%0D%0A%3C%2Fhtml%3E

Firefox 2, Opera 9.2, Safari 3: shows the text "Body".
Firefox 3 (2007-08-05), IE7: shows no text.

CDATA acts inconsistently too:

http://software.hixie.ch/utilities/js/live-dom-viewer/?%3Chtml%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1999%2Fxhtml%22%3E%0D%0A%3Chead%3E%0D%0A%3Ctitle%3E%3C%2Ftitle%3E%0D%0A%3C%2Fhead%3E%0D%0A%3Cbody%3E%0D%0A%3Cp%3E%3C!%5BCDATA%5B%20%5B%3E%20%5D%5D%3EBody%3C%2Fp%3E%0D%0A%3C%2Fbody%3E%0D%0A%3C%2Fhtml%3E

Firefox 2, 3: shows "Body".
Safari 3, IE7: shows "]]>Body".
Opera 9: shows no text. (It's weirder if you use a static file instead 
of the Live DOM Viewer - it shows "y".)

<?xml ...?> declarations cause more inconsistency since they make IE6 
render in quirks mode.


Only the subset of XHTML documents which also comply with some Appendix 
C-like (but much stricter and more detailed) guidelines could be served 
as text/html without practical problems. For interoperable processing by 
existing UAs, normal XHTML documents (i.e. those not carefully 
constructed to work as HTML) must not be text/html.

-- 
Philip Taylor
philip@zaynar.demon.co.uk