125710 - Can't dynamically create stylesheets (style, text/css, createCSSstyleSheet)

Status: VERIFIED FIXED

(Core :: DOM: Core & HTML, defect, P3)

Description

[Robert Kieffer]

Build 2002020406

Dynamic creation of style sheets doesn't seem to work.  I've been trying to to
do this with no success.  The W3C spec specifies two ways of doing this, neither
of which work:

1.) Sect. 2.2.2 of
http://www.w3.org/TR/2000/REC-DOM-Level-2-Style-20001113/css.html talks about
the createCSSStyleSheet() method, but this doesn't appear to be implemented in
Mozilla.

2.) Sect. 1.4 of
http://www.w3.org/TR/2000/REC-DOM-Level-2-Style-20001113/stylesheets.html#StyleSheets-Association
 says explicitely that style sheets can be created by creating a STYLE element
and setting it's type to 'text/css'.

There is an existing bug about method #1
(http://bugzilla.mozilla.org/show_bug.cgi?id=63850) that, correctly, makes the
point that there is no spec'ed way of attaching the sheet to a document.

However, method #2 *should* work.  I've attached a test case that tries this
approach, but no matter what I do, the 'sheet' property of the element is always
null.  The test case writes out the properties of a static STYLE element (which
I can add rules to) and the dynamic element (which I can't because of the
missing sheet), and everything looks pretty good between the two, except for the
null 'sheet' property.

The workaround is to create an empty STYLE block in your HTML and just use that
to insertRule()'s into.  (There are cases where this may not work for us here at
DIG, but I'll discuss prioritization of this offline with bcleary).

§

Comment 1

[Robert Kieffer]

Attachment: Test case for (trying to) create dynamic style sheet

Comment 2

[Boris Zbarsky [:bzbarsky]]

I've been poking at this code....

We'd ideally like to create the sheet at inserting-into-document time as the
spec says.  At that point we'd just take an empty string, parse it into
stylesheet data, and Unfortunately, we insert normal <style> elements into the doc
_before_ parsing their contents.  Even worse, if the <style> element has a title
(hence the sheet is alternate) the stylesheet parsing/creation is asynchronous
with the parsing of the HTML document...  So we can't just "parse first, insert
later".

The issue is confused by the fact that we seem to support either 
<style href="..."> or <style src="..."> or some mix depending on how you read
the comments and the code....  Do we _ever_ have <style> elements loading
non-inline sheets??

Peterv?  Any ideas?  You did this dynamic stuff for <link>, right?

Comment 3

[Boris Zbarsky [:bzbarsky]]

Another thought....  We could add a method on nsIStyleSheetLinkingElement that
will basically say "data coming up".  Then the content sink will call that
method before appending to the doc.  If said method has been called the <style>
element will hold off on creating an inline sheet because the CSSLoader is
handling it. If the method has not been called, the element will create the
sheet upon being appended to the document.

That seem reasonable?

Comment 4

[Boris Zbarsky [:bzbarsky]]

OK.  More investigation shows:

1) we call SetEnableUpdates(FALSE) in the content sink.  So in fact updating
   dynamically in SetDocument or SetType is OK.
2) The content sink increments mStyleSheetCount twice per inline sheet.  This
   seems wrong, but correct me now if I'm missing something.
3) The best solution seems to be to make nsStyleLinkElement::UpdateStyleSheet
   aware of inline stylesheets and then move the inline sheet stuff out of the
   content sink and into UpdateStyleSheet.

Comment 5

[Fabian Guisset]

Boris, there's already a patch to fix this in bug 34849, I believe.

Comment 6

[Bob Clary [:bc] (inactive)]

Fabian, nice catch! 

Boris, how does your analysis reflect the state of bug 34849? Should we just
dupe against that bug? If so, please carry over the DIGBug status.

Comment 7

[Boris Zbarsky [:bzbarsky]]

well, the patch in bug 34839 would fix this.  :)  Dupping to that one.

*** This bug has been marked as a duplicate of 34849 ***

Comment 8

[Robert Kieffer]

Re-opening and marking as dependent on bug 34849.

This is not quite a duplicate.  It addresses a DOM spec issue that's not
discussed in bug 34849 - namely that adding a style sheet element (and,
specifically, setting the type to 'text/css') is a recommended way of adding
style sheets to a document.

Given that the fix for 34849 should fix this, it might make sense to assign it
to [e-mail] (but I don't seem to have permission to do that).

Comment 9

[Johnny Stenback (:jst)]

bz's favourite subject, reassigning! :-) bz, feel free to hand this back to me
if you don't want it.

Comment 10

[Boris Zbarsky [:bzbarsky]]

I'll take this.  :)  I'm gonna try to make glazou fix this as part of 34849; if
that fails at least he's making the arch changes that should make this an easy
fix.  :)

Comment 11

[Arun Ranganathan]

nominating nsbeta1 .  Turns out this is asked for by developers to our feedback
alias.

Comment 12

[Boris Zbarsky [:bzbarsky]]

I'm going out of town in two days and not getting back till after 1.0 freeze. 
Setting realistic milestones for all 1.0 bugs that depend on other bugs or on
possible interface work.

Any help on getting these fixed would be much appreciated...

Comment 13

[Peter Van der Beken [:peterv]]

This will be fixed by my upcoming patch for bug 34849 (I just tried it and the
testcase works in my tree).

Comment 14

[Boris Zbarsky [:bzbarsky]]

As a note, please test the same script but with inserting the <style> element
into the document first, _then_ setting the type attr.

Comment 15

[Sivakiran Tummala]

adding to cc list

Comment 16

[Heikki Toivonen (remove -bugzilla when emailing directly)]

There is one milestone before 1.1alpha, let's try to get this in 1.0.1

Comment 17

[Sivakiran Tummala]

i think this is important for MachV and according to comment 13, if the patch
for bug 34849 will fix this, i think this should be a nsbeta1+

Comment 18

[Peter Van der Beken [:peterv]]

Fixed by patch for bug 34849.

Comment 19

[Prashant Desale]

Verified on 2002-05-23-08-trunk.