[whatwg] <output> should not be barred from constraint validation

[Mounir Lamouri]

Hi,

At the moment, three form elements are barred from constraint
validation: object, fieldset and output. I can understand why object and
fieldset are barred from constraint validation but I think output could
use the constraint validation.

Indeed, it could be nice to be able to use setCustomValidity() on
<output>. IMHO, it is part of the use case of <output>: this element
should represent the result of a calculation and we may want to do a
validation check on this result.
For example, we could imagine a web application to choose courses in an
university and you have to select between 12 and 18 credits. <output> is
the best way to represent the total credits used and it would be easy to
make it invalid when the sum is not correct.

Feedback is welcome :)

Thanks,
--
Mounir