Re: "Unknown Parse Mode!" when validating with DOCTYPE chosen to force STRICT mode in Mozilla

On Thursday 2006-07-13 12:07 +0100, Philip TAYLOR wrote:
> David, could you please let Olivier and I know why/how using a SYSTEM
> identifier causes Mozilla to use Full Standards Mode ?
> 
> 	http://developer.mozilla.org/en/docs/Mozilla%27s_DOCTYPE_sniffing
> 
> This question arose because my use of a SYSTEM doctype causes the
> validator to be unsure whether to use SGML or XML rules for parsing ...

The goal of DOCTYPE sniffing was that newly-written pages should be in
standards mode and old pages should be in quirks mode.  In other words,
DOCTYPE sniffing was used as a heuristic to determine which pages were
written after Mozilla became a known user-agent on the Web (as I wrote
in the URL you cite).  Since pages with SYSTEM doctype declarations were
not common on the Web around 2001, such pages are treated as pages
written with knowledge of Mozilla's existence, and are therefore handled
in standards mode.

-David

-- 
L. David Baron                                <URL: http://dbaron.org/ >
           Technical Lead, Layout & CSS, Mozilla Corporation