102303 - getAttribute on a HTMLTableRowElement returns nothing

Status: VERIFIED INVALID

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

Description

[Peter Snow]

From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.4+) Gecko/20010927
BuildID:    2001092708

All getAttribute methods on the HTMLTableRowElement return nothing. However,
directly addressing the attribute such as
HTMLTableRowElement.sectionRowIndex returns the correct value. For example:

var tr = document.getElementById("tr2");
tr.getAttribute("sectionRowIndex") returns nothing

but calling tr.sectionRowIndex returns the correct value. 
Both methods above work correctly in IE (5.5 and 6.0). 
I've attached a test case that demonstrates this. Also reproducible
with 0.94 on NT.



Reproducible: Always
Steps to Reproduce:
See test case.

Comment 1

[Peter Snow]

Attachment: Test case for getting attributes from a HTMLTableRowElement

Comment 2

[Fabian Guisset]

Ok here's my explanation... SectionRowIndex is not an attribute of the <tr> HTML
tag. However it is a property of the HTMLTableRowElement DOM object.
getAttribute returns the value of the attribute of the element. But since our tr
object doesn't have such an attribute, it returns an empty string. However
tr.sectionRowIndex works as expected.
Did I miss something?

Comment 3

[Johnny Stenback (:jst)]

Fabian is correct, tr.foo != tr.getAttribute("foo") as per the DOM spec. IE is
broken wrt this. INVALID>

Comment 4

[Peter Snow]

Thanks for the clarification. I understand the point that sectionRowIndex does
not have an equivalent in the HTML 4.01 spec, and as such is not an attribute of
the <tr> tag per se. However, is not a <tr> tag an implementation of the
HTMLTableRowElement interface? As such, it should be able to return a value for
the sectionRowIndex attribute. It does, of course, but only via
tr.sectionRowIndex. Is not exposing properties in this way deprecated (section
2.5.1 of the DOM 1 HTML spec) and we are not all encouraged to use getAttribute
instead? Does it not make it more difficult to use generic methods such as
getAttribute, if there are many exceptions to this rule? Thanks for your insight.

Comment 5

[Johnny Stenback (:jst)]

All properties don't have equivalent HTML attributes, some properties are
exposed only as properties of JS objects.

Comment 6

[Fabian Guisset]

Peter,
I'll try to explain quickly why this is invalid:
There is a difference between an attribute defined by the mark-up language, and
an attribute defined by the Document Object Model. They have the same name, but
often we call DOM attributes "properties". I think you are confusing the two
kind of attributes, because the W3C happened to define DOM attributes for most
of the mark-up attributes. For example the "align" attribute of a div can be
retrieved using div.getAttribute("align"), but the DOM also defines an "align"
property on the HTMLDivElement interface.
DOM attributes can _only_ be retrieved or set using Interface.attribute, and
mark-up attributes can _only_ be retrieved or set using Element.get/setAttribute().
Feel free to email me any more questions :-)
VERIFIED invalid.