[whatwg] ALT and equivalent representation

[Shannon]

Benjamin Hawkes-Lewis wrote:
>
> But whether we need a mechanism for denoting differing img elements 
> combine to form a single image is a very different question from 
> whether alt should be optional or required. You seem to be conflating 
> them.
>
>
How can <img alt> or <img alt=""> not be related to making alt optional?

Both represent a total lack of information with no explicit relationship 
to any other element. There is no way a parser can resolve whether this 
information is supplied previously or not. If the parser can't tell then 
it can't validate the alt requirement - thereby mandating that alt (that 
is the text, not the empty attribute) be optional for a conforming 
document (as far as a validator knows anyway). Once alt text becomes 
optional then it is likely that many designers/templates/wysiwyg 
applications will simply insert alt="" into every image to pass 
validation without consideration for blind users. It is this situation I 
am trying to avoid. A valid document should provide valid alt 
information, not empty ones. An altgroup supports this - empty alt tags 
do not.

Shannon