303019 - Incorrect handling of nested HTML open comments (<!--).

Status: RESOLVED DUPLICATE of bug 290070

(Firefox :: General, defect)

Description

[Erik]

User-Agent:       Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322)
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.10) Gecko/20050716 Firefox/1.0.6

The page http://www.kythra.net/blog/firefox.htm is a snapshot of my blog. It 
should look like http://www.kythra.net/blog.
The only difference is that the snapshot contains the following code:
<!-- WebHost4Life.com Code Begin 
<a href="http://www.WebHost4Life.com/default.asp?refid=MarkHWagner">
<img id="Header1_HeaderAd" src="Skins/Cogitation/Images/WebHosting.gif" 
alt="Join WebHost4Life.com" border="0" />
</a>
<!-- WebHost4Life.com Code End -->

The gross formatting problems are a result of there being a "<!--" inside the 
body of the comment and firefox attempting to parse the second comment opener.

The correct behavior when handling nested comments is to ignore everything in 
a comment until the comment closer (-->) is reached.

This is a Firefox-specific bug, I have tested the same code on Mozilla for 
OSX, and not seen bug.

Reproducible: Always

Steps to Reproduce:
1. Navigate to any moderately complex page that has a nested HTML open-
comments (<!--)
Actual Results:  
Firefox gets confused when seeing nested comment openers (<!--) and comments 
out HTML outside of the comment; HTML that should be rendered normally.

Expected Results:  
The correct behavior when handling nested comments is to ignore everything in 
a comment until the comment closer (-->) is reached. Everything after the 
comment should be rendered as usual.

Comment 1

[shadytrees]

Attachment: Testcase without doctype (quirks mode). Does not occur in quirks mode.

Comment 2

[shadytrees]

Attachment: Testcase with doctype (standards mode). Does occur.

Comment 3

[shadytrees]

In standards mode, Firefox emulates tree-like behavior (if you open within
comment, you have to close TWO comments to get all comments to close). "<!--
comment <!-- comment -->" still has one more comment to close. So Firefox goes
on a hunt for another comment. And it gets one. You have a "-- Unknown" in
firefox.htm. Firefox pairs up that dash with the nearest ">", which happens to
be a tag (</div> or something).

In quirks mode, Firefox will close all comments open as soon as it hits a close
comment atom.

All in all, fun.

Comment 4

[shutdown]

XHTML is XML, and in XML "--" in comment is INVALID.
http://www.w3.org/TR/REC-xml/#sec-comments

Comment 5

[O. Atsushi (Torisugari)]

This is a dupe of bug 290070

Though I guess there'd be a bug older than that...

Comment 6

[José Jeria]

*** This bug has been marked as a duplicate of 290070 ***