[html4all] several messages about alt

[Henri Sivonen]

On Apr 13, 2008, at 14:15, Ben Boyle wrote:
>
> I think I understand this, but not sure.
>
> There is a difference between checking one's HTML syntax is valid, vs
> evaluating its accessibility (or any other value-based quality
> measure). You're advocating keeping these separate. I can see the gulf
> between the two.
>
> Where does "conformance" fit in on the scale?


It depends on what kind of conformance is meant. First, there's the  
question of conformance to what? To HTML5? To WCAG? Second, there's  
the issue that overall conformance criteria may have parts that are  
not machine checkable.

In theory, HTML5 conformance and HTML5 validity are the same thing. In  
practice, though, people tend to think that validity is what a  
validator checks, which is machine-checkable conformance criteria.

Examples of non-machine-checkable conformance criteria:
  * "The img must not be used as a layout tool." (HTML 5)
  * "Authors must only use elements, attributes, and attribute values  
for their appropriate semantic purposes." (HTML 5)
  * "Content MUST NOT use a code point for any purpose other than that  
defined by its coded character set." (Charmod)
  * "Images of text are only used for pure decoration or where a  
particular presentation of text is essential to the information being  
conveyed." (WCAG 2.0)

-- 
Henri Sivonen
hsivonen at iki.fi
http://hsivonen.iki.fi/