50574 - Formatting tags in tables stop working after division tags

Status: RESOLVED WONTFIX

(Core :: Layout, defect, P3)

Description

[John Keiser (jkeiser)]

Sorry, I don't know what you call them, but I will define terminology:

Formatting tags: B, U, I, FONT (anything which changes the look of text but does
not divide it)
Division tags: DIV, TABLE, H1 (anything which divides the text layout-wise, even
if it is also a formatting tag)

As you can see in the testcase, the text that says it should not be bold, is bold.

So the story goes like this: I found a weird phenomenon testing one of my
documents and reduced it to a testcase.  Specifically, what seems to be
happening is three conditions together that make text appear with the wrong
formatting (if you remove any of them things work fine):

1. The text must be inside a table cell.
2. A formatting tag must precede the text.
3. There must be a division tag inside the formatting tag.

Basically, the structure must look like this:

<TABLE><TR><TD>
<formatting tag>
<division tag></division tag>
</formatting tag>
Text that formatting tag should not apply to but does anyway.
</TD></TR></TABLE>

I have tried several combinations now: FONT and B for the formatting tag, and
DIV and H1 for the division tag, and it comes out the same.  SPAN for the
division tag does not come out that way, so I guess it doesn't count as a
division tag.

Strange thing: A TABLE inside the formatting tag acts like a division tag, but
with the added effect that the text inside the TABLE tag is not formatted with
the outer formatting tag (which I would expect as a programmer).  I do not know
if this is a bug (maybe some weird bit of the spec), but someone might wish to
look into it.

It seems like this must be the formatting portion of the renderer; I think I
ruled out the parser.  I gave the B an ID and printed innerHTML from JavaScript
... it didn't include the words "This Should Not Be Bold".

Comment 1

[Hixie (not reading bugmail)]

What you call a 'formatting tag' is called an 'inline element'.
What you call a 'division tag' is called a 'block element'.

The only problem is that there is a general rule that inline elements may not
contain block elements. So Mozilla has to do all kinds of acrobatics when it
comes across this case -- for example,  <B> <H1> </H1> </B> -- to try to make
it work. 

The W3C suggest the use of stylesheets for formatting instead of formatting 
tags. See http://www.w3.org/TR/REC-CSS1 for more details.

Comment 2

[John Keiser (jkeiser)]

Could you give me a head start on where to look in the code if I wanted to try 
and fix this myself?  It's rather counterintuitive behavior, even if the spec 
does say that.  Even a general module would be useful.

Comment 3

[Hixie (not reading bugmail)]

Sure. I believe the code to change is in 
   .../mozilla/htmlparser/src/nsElementTable.cpp
You may wish to see bug 47827 where a similar bug (but this time where we got
the standards wrong) was recently fixed.

Note, though, that unless you have a very strong reason to fix this (e.g., a
top100 site breaks on it) then there are many more somewhat more important bugs
that you could help fix...