Question

I am using FF with Jaws and I have set the role of “scrollbar” on a div but it is not getting picked up by Jaws:

The wai aria spec says aria-valuemax, min and now are compulsory attributes for the scrollbar role but am not really sure it makes sense in this case since all I have is a vertical scrollable area…thoughts?

FF 14.0.1
Jaws 13.0

Answer 1

Currently, JAWS does not support scrollbar role. So if you specify an element with an unsupported role it may result in unexpected results when using JAWS for example, it sometimes tries to announce some of the states and in other cases it just ignores them.

And regarding your second question about aria-valuemax, aria-valuemin and aria-valuenow, these attributes help in determining how much percentage of the scroll contents is being displayed in the viewing area with respect to the position of the thumb. It will help a blind user to know how much more the contents can be scrolled up or down.

And aria-valuenow can be calculated with respect to the thumb position and the height of the scrollbar as below:

Suppose if the viewing area has a height of 200px and thumb height is 30px. So initially when the thumb position is 0 from top then the contents currently displayed in the area is aria-valuemin=aria-valuenow and when the thumb is at 170px from top, the scroll contents is fully displayed aria-valuemax=100.

If you are interested you can take a look at this demo on calculating aria-valuenow. You can tab through the elements and JAWS does not announce any role but seems to announce the value initially and does not update the value in the same way it does for a slider

See also:

• Official JAWS aria support list