270926 - navigation fails with duplicate anchor NAMEs (works with duplicate IDs)

Status: RESOLVED INVALID

(Core :: DOM: HTML Parser, defect)

Description

[Michael Newton]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.0; en-CA; rv:1.7.5) Gecko/20041107 Firefox/1.0
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-CA; rv:1.7.5) Gecko/20041107 Firefox/1.0

If a page has elements with duplicate NAME attributes (not valid HTML I know)
you cannot navigate to either of the elements.
However, if the ID attribute is used instead, a link will take you to the first
occurence of the specified ID, which I would think is the preferred behaviour.
This may be the same issue demonstrated by bug 217235 but I'm not sure.

Reproducible: Always
Steps to Reproduce:
1.Load first test case
2.Click the link


Actual Results:  
No navigation

Expected Results:  
Navigates to first image

Comment 1

[Michael Newton]

Attachment: testcase using NAME attribute

Comment 2

[Michael Newton]

Attachment: testcase using ID attribute

Comment 3

[Martijn Wargers (dead)]

You're setting the name attribute on img elements. I don't think they are valid
destination anchors.
See:
http://www.w3.org/TR/REC-html40/struct/links.html#h-12.1.1
"Destination anchors in HTML documents may be specified either by the A element
(naming it with the name attribute), or by any other element (naming with the id
attribute)."
So I think this bug is invalid.
Note that you first example doesn't work even with one name attribute. But it
does work when the named elements are anchors.

Comment 4

[Michael Brown]

Attachment: Test using duplicate name anchors that shows they work

This test case shows that duplicate anchors using name do in fact work.  The
browser scrolls to the first occurence.

Comment 5

[Michael Brown]

Attachment: Test using duplicate name anchors and display:none

If however the first anchor among duplicates is styled not to display
(display:none) then the browser does not scroll do anything with the #test
link.
The behaviour is clearly to scroll to the first of a set of duplicates, if that
happens to be "display:none" then it gives up.

A more tolerant behaviour would be to scroll to the first VISIBLE anchor among
duplicates.  

The same problem exists with duplicate ID attributes too.  If the first of the
duplicates is "display:none" then the browser does nothing.

Michael.

Comment 6

[Michael Newton]

Closing per comment 3
I was under the mistaken belief that NAME and ID were largely interchangeable
when it came to named anchors.  The issue described in comment 4 and 5 may
warrant a separate bug.