[whatwg] hit regions: limited set of elements for fallback content

Rik Cabanier cabanier at gmail.com
Mon Feb 17 22:09:09 PST 2014

On Mon, Feb 17, 2014 at 8:20 PM, Ian Hickson <ian at hixie.ch> wrote:

> On Mon, 17 Feb 2014, Rik Cabanier wrote:
> >
> > The current spec for hit regions restricts what elements can be used as
> > fallback content [1]:
> >
> > [...]
> >
> > Why is there this limitation?
> It supports the content model restrictions, which are there to avoid
> authors making mistakes that harm accessibility (amongst other things).
> Reasons for content model restrictions are discussed in more detail in the
> introduction to the spec:
> http://whatwg.org/html#restrictions-on-content-models-and-on-attribute-values
> If there are specific use cases that can't be done given the current
> restrictions, please let me know; we can definitely consider relaxing some
> of the restrictions. (It's very hard to tighten restrictions, but
> comparatively easy to relax them, which is why we start them on the strict
> side rather than on the relaxed side.) So far, all the use cases that
> people have brought up for things that can't be done within the current
> restrictions also happen to be things that canvas is actually really bad
> at doing at all.

Were those use cases posted to this list?

So, you wouldn't want the same limitations as for regular HTML elements?
The canvas fallback content could be what is exposed to the user so it
might be painful for the author to match it up with hit regions.

I agree that relaxing it to any element could allow non-sense. Is there a
clear definition of what is disallowed or allowed in HTML? I couldn't find
it in the spec.

> There's another non-normative section that goes into more
> detail about these kinds of things:
>    http://whatwg.org/html#best-practices

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