I'm currently working on the accessibility of an rich web application that includes taking a signature with jSignature, and part of the brief from the client is it must be very accessible.
Much of the accessibility work is done, but in respect to the signature itself, VoiceOver on iOS doesn't allow selection of the box, and so it reads nothing, nor does it allow the user to 'sign' with a finger, as is the purpose of the box. This is the case with any ARIA directives we've tried (aria-polite, aria-grabbed, role).
It seems like VoiceOver cannot see the JSignature box at all.
I believe you are looking for the following trait: