What kind of error reporting were we talking about here? Was it browser console output like "invalid aria-valuenow", or was it something like reporting a -999 for invalid values (through platform API)?

I guess the related question is what to return if the aria-valuenow is missing (where is shouldn't be missing).

From today's call:
Investigate using a null value.
Is there value in raising an event?

*** Bug 6885 has been marked as a duplicate of this bug. ***

Cynthia to ask the IE guys what browsers should do in this case

David to find out what Mozilla team does

From Cynthia via e-mail:

"Don't use -999 type errors in the API, because these features are too generic to be sure that -999 (or any value) is always wrong.  Error reporting should be done through a console.  We still need to design that, but I don't think it's a p1 feature."

I think we need more here. Seems weird to say what error shouldn't be returned without saying what should be returned. Keeping this one open for the next editor's draft.

06/26/09: No error through API. User agents may return an error through a debug console.

Re-opened in error.