Do <td> elements inside a <thead> get automagically promoted to act like <th>

[patrickhlauke]

Picking up from an old conversation over here w3c/html#819 there seemed to be some throughs from @LJWatson that, due to the wording for the <thead> element https://html.spec.whatwg.org/#the-thead-element there's a clear indication/implication that a <td> inside a <thead> will also automagically be considered the same as a <th> ?

However, if that is indeed the intention, this concept should be explicitly explained, particularly in the definition for the <td> element itself? https://html.spec.whatwg.org/#the-td-element

/cc @chaals @stevefaulkner

[andrewnicols]

Anything we can do to help facilitate this discussion and get an outcome?

[patrickhlauke]

Returning to this dangling thread ... I believe the situation touched on in w3c/html#819 is still handwaved/unresolved here. I think it would be worth to unambiguously work out if <td> elements inside the <thead> are to be essentially treated as <th> elements (and that they should be exposed as such in the accessibility tree) due to the wording in the spec

The thead element represents the block of rows that consist of the column labels (headers)

or if there is no such intention of implicitly "upgrading" a <td> to a <th> when it's inside a <thead>, in which case the wording in the spec may need to be expanded to provide more nuance.

/cc @LJWatson @chaals @stevefaulkner

[stevefaulkner]

-1 from me, it is not uncommon the have a <td> element in a <thead> that does indeed represent a <td> not a <th>

[patrickhlauke]

@stevefaulkner so -1 meaning "the phrasing in the spec should be reworded to give more nuance", i assume...

[scottaohara]

seems like this could be updated to say something like:

...that consist of the column labels (headers) and related cells for the parent table element,...

the first example provided in this section uses td elements to provide a description of what the previous row of actual table header represents - so to me that seems an overt example that td isn't intended to universally become table headers.

[patrickhlauke]

Proposed a small tweak #9552