[whatwg] Definition of alt= attribute

Matthew Paul Thomas mpt at myrealbox.com
Tue Jan 24 03:36:58 PST 2006

On 24 Jan, 2006, at 5:43 AM, dolphinling wrote:
> Matthew Paul Thomas wrote:
>> Bizarre but serious conclusion: alt= should be optional for <img> in 
>> documents where a <meta name="generator"...> element is present.
> How about "Authoring tools MUST only provide alternate text that the 
> author explicitly requests,

That would seem to prevent, for example, Microsoft FrontPage from 
generating the obvious alt text for an Image Composer image that 
consisted only of text sprites. (And since Microsoft continue to 
misimplement the existing spec for alt=, it wouldn't be a good idea to 
trust them to interpret "explicitly requests" the way you want.)

> and especially MUST NOT provide alt="" unless the author specifically 
> says that the alternate content is empty. Authoring tools SHOULD make 
> it obvious to the author what the meaning of alt= is, for example with 
> the string "What text should be used if the image cannot be 
> displayed?""


That example of awful alt= text was apparently made with vi. Would vi 
be violating your SHOULD, for not making the meaning of alt= obvious?

> ...
> Problems with this approach include the following: First, it could be 
> interpreted as disallowing pseudo-AI. This could be fixed with a note 
> saying "This should not be interpreted as disallowing pseudo-AI in 
> authoring tools, but even a pseudo-intelligent authoring tool MUST NOT 
> assume an empty alt text."

I think that text fails the "wtf?" test. Does it cover the Image 
Composer example above? Nobody would be able to tell.

> Second, it could force authoring tools to produce invalid documents if 
> the author did not provide any alt text. However, those documents 
> would be non-conformant anyway, so this is not a huge problem.
> ...

It would be a problem as long as "generates valid HTML" is considered a 
feature separate from conformance, since software can guarantee the 
former but not the latter. And I don't think anything in an HTML 5 spec 
could prevent validity from being seen as a feature. That's why I 
propose the <meta name="generator"...> exception for compulsory alt=.

Matthew Paul Thomas

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