On Jul 26, 2012, at 8:06 AM, Richard Schwerdtfeger <schwer@us.ibm.com> wrote:
> Regarding this issue and supporting this portion of the change proposal:
>
> http://html5.org/tools/web-apps-tracker?from=7028&to=7029
>
> This following text is buried in this change proposal and absolutely needs to go from addHitRegion processing:
>
> "The arguments object's control member is not + null but is neither an a element that + represents a hyperlink, a + button element, an input element whose + type attribute is in one of + the Checkbox or + Radio Button states, + nor an input element that is a button."
>
> This states that no aria widgets are allowed and many other html5 elements inlcuding control types such as text and range. The HTML5 specification is designed to provide keyboard navigation within fallback content. All HTML5 elements support tabindex. This includes elements like <div> and <span>. This step essentially removes essential features of HTML need to support an accessible canvas solution. So, this line of text MUST go.
>
> We have already implemented work keyboard enabled ARIA content in canvas fallback content that drives screen readers and this restriction would cause magnifiers to not work.
>
> This text needs to be changed to:
>
> "The arguments object's control member references an element with a valid id."
>
To add some context to Rich's point (which I did not understand until I read the full diff text), it appears that hit regions backed by elements are limited to hyperlinks, buttons, checkboxes and radio buttons. If you specify any other element, the method will throw an exception. It's not clear to me why other elements are categorically excluded from backing a hit region.
Regards,
Maciej