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

[Ian Hickson]

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. There's another non-normative section that goes into more 
detail about these kinds of things:

   http://whatwg.org/html#best-practices

-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'