268442 - quirks mode used for popup if XHTML strict doctype and XML prolog are written with separete document.write commands

Status: RESOLVED FIXED

(Core :: DOM: HTML Parser, defect)

Description

[tarquin]

User-Agent:       Opera/7.54 (X11; Linux i686; U)  [en]
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.5) Gecko/20041103 Firefox/1.0RC2

If the contents of a popup are dynamically written, and the XHTML strict doctype 
tag and XML prolog are written with separate document.write commands, Mozilla/
Firefox/Gecko will use Quirks mode to render the popup contents even though it 
should use standards compliant mode. Checking the source of the popup correctly 
shows that it was all written correctly, but it still uses the wrong mode.

Reproducible: Always
Steps to Reproduce:
1. open a popup
2. use document.write to write its contents, using separate document.write 
commands for the XHTML strict doctype tag and the XML prolog
3. Mozilla/Firefox/Gecko will use the wrong rendering mode

Actual Results:  
Quirks mode is used for rendering popup contents

Expected Results:  
Standards compliant mode should have been used to render popup contents

Comment 1

[Blake Kaplan (:mrbkap) (inactive)]

Confirming. I'm not entirely certain when we sniff for a doctype in the parser,
but I have a suspicion that we only check on the first nsParser::Parse(nsString
..., ...) so the two document.write()s throw us off, or something like that.

Comment 2

[Boris Zbarsky [:bzbarsky]]

That's correct.  We only look for the doctype in the first chunk of data the
parser gets; the behavior noted in this bug can be reproduced with network
packets too (simply by having a few kilobytes of whitespace between the XML decl
and the doctype).

We can't simply assume anything starting with an XML prolog is standards mode,
though... if nothing else, some of it needs to be almost standards.

Comment 3

[Uri Bernstein]

(In reply to comment #2)
> the behavior noted in this bug can be reproduced with network
> packets too (simply by having a few kilobytes of whitespace between the XML decl
> and the doctype).

Bug 261892 describes such a situation.