Spinner: inconsistency with null value and aria-valuenow property

[clown]

When a spinner is set to a null value via spinner.attr('value', null), the value of the spinner and its aria-valuenow property do not match:

spinner.attr('value') -> NaN

dijit.getWaiState(spinner, 'valuenow') -> "" (the empty string).

The ARIA specification for spinner is not clear on this case: see http://www.w3.org/WAI/PF/aria/#spinbutton.

FWIW, I think the spinner's value and its aria-valuenow should always match. In this case, aria-valuenow should also be NaN.

Ultimately, it depends on what the ARIA working group decides.

[clown]

Noting that the ARIA specs on "valuenow" imply that if the value is unknown, then valuenow should be absent. Quoting from http://www.w3.org/WAI/PF/aria/#valuenow:

If the value is not known (as often occurs with progress bars) then the valuenow attribute should not be set at all. If the valuenow attribute is absent, no information is implied about the current value.

[becky]

Note that when this is fixed, the tests/form/robot/test_Spinner.html test should be updated to include a test for a null aria-valuenow. The current test is commented out.