Testing aria-errormessage

Initial findings

Check the official ARIA 1.2 documentation on aria-errormessage rules before testing!

Tested with iPhone, VoiceOver on Safari:

Potential bug...

I think that display:none or attribute hidden should have the same effect as visibility:hidden, but it seems that they do not... To be continued...

Authors MAY use aria-errormessage on an object that is currently valid, but only if the element referenced by aria-errormessage is hidden, because the message it contains is not pertinent.
—ARIA 1.2 about aria-errormessage

Test form

Following input will always be invalid when you submit the form