Re: Web Accessibility Tutorials: Images and Tables

On 16 Sep 2014, at 19:37, Olaf Drümmer wrote:

> Hi Eric,
>
> the context for this discussion is
>  http://www.w3.org/WAI/tutorials/tables/
> though it seems somebody change the two instances of
>  alt
> into
>  alt=""
> already.

So it seems that the issue is resolved. Thank you for your feedback.

> Regarding the syntax discussion:
> I am interested in learning where you have found an indication that 
> using alt without a value is just fine. I have provided sources that 
> make it very clear for HTML4 that it is **incorrect** (alt is not an 
> attribute of type boolean), and that one can argue it is not correct 
> for HTML5 (and I admitted the wording is not very crisp, but wiithout 
> wording elsewhere that seems to allow such use of alt I would insist 
> my interpretation is correct).

In HTML5 it says
   http://dev.w3.org/html5/html-author/#empty-attr

   “An empty attribute is one where the value has been omitted. This 
is a **syntactic shorthand for specifying the attribute with an empty 
value**, and is commonly used for boolean attributes.”

(Emphasis mine. )

In HTML4 that was not _meant_ to be the case, yet browsers did it like 
that all the time, so I guess they are just paving cowpaths there.

Best, Eric

>
>
> Olaf
>
>
> On 16 Sep 2014, at 16:54, Eric Eggert <ee@w3.org> wrote:
>
>> hi Olaf,
>>
>> On 16 Sep 2014, at 16:33, Olaf Drümmer wrote:
>>
>>> Hi Eric,
>>>
>>> after some research I found this (3.2.3.1 Empty Attribute Syntax )
>>>  http://dev.w3.org/html5/html-author/#empty-attr
>>>
>>> Also see:
>>>  http://www.w3.org/TR/html/infrastructure.html#boolean-attributes
>>> though wording is much less straightforward here.
>>>
>>>
>>> So except for boolean attributes an attribute without a value is 
>>> illegal.  And even for boolean attributes it is illegal for XHTML. 
>>> This implies that the synatx used on the mage tutorial overview page 
>>> is simply incorrect  correct and requires fixing.
>>
>> The empty attribute syntax is not only valid for boolean attributes, 
>> just “commonly used” for them. The spec is quite unclear for 
>> developers here. Basically the behavior is like this:
>>
>> If an attribute is used without a value, assume its value is an empty 
>> string (attr -> attr="").
>> If a boolean attribute’s value is an empty string, set it to true 
>> (bool="" -> bool="bool").
>>
>> That means an attribute like alt would transform to alt="";
>> and an attribute like disabled would transform to disabled="" and 
>> then to disabled="disabled".
>>
>>
>> That said, I’m a bit lost on where we have used (or should have 
>> used??) an alt without an empty value. We nowhere advices to use the 
>> alt without the empty string attached. It is always
>>
>> alt="" (which is fine in XHTML as well as HTML)
>>
>> and not
>>
>> alt (which is syntactically correct in HTML, but not used for the 
>> reasons outlined in my previous email)
>>
>> alone.
>>
>> Can you point me to the section of the page you have an issue with? 
>> And to clarify, it could probably be helpful how you’d phase the 
>> sentence affected.
>>
>>> BTW - Personally I think, when writing a decent spec it should not 
>>> have an impact that some agents can handle illegal syntax - the spec 
>>> should simply get it right.
>>
>> I think this is a different discussion ;-)
>>
>> Best, Eric
>>
>>>
>>>
>>>
>>> Olaf
>>>
>>>
>>> On 15 Sep 2014, at 18:38, Eric Eggert <ee@w3.org> wrote:
>>>
>>>> Hi Olaf,
>>>>
>>>> [3]
>>>> The last bit goes back to my limited familiarity with details in 
>>>> HTML:
>>>> - is
>>>> alt
>>>> really equivalent to
>>>> alt=""
>>>> ?
>>>> - if so, why do the examples in W3C WAI related content I have run 
>>>> into (and definitely those in the image tutorial) use
>>>> alt=""
>>>> ?
>>>>
>>>> In modern HTML5 browsers, alt will be interpreted as alt="", but I 
>>>> don’t consider using this as best practice, especially when 
>>>> educating website authors:
>>>>
>>>> Having the ="" in there show that the empty alt is a deliberate 
>>>> decision and not something forgotten.
>>>>
>>>> Older browsers or assistive technology might treat alt without a 
>>>> value as missing and might announce the filename instead of 
>>>> nothing.
>>>>
>>>> Using two syntaxes like this with minor differences and little to 
>>>> no gain would only confuse some people and would be hard to 
>>>> explain, imho.
>>>>
>>>> Best, Eric
>>>>
>>>> --
>>>>
>>>> Eric Eggert, Web Accessibility Specialist
>>>> WAI-ACT Project
>>>>
>>>> I’m yatil on IRC.
>>>>
>>
>>
>>
>>
>> --
>>
>> Eric Eggert, Web Accessibility Specialist
>> WAI-ACT Project
>>
>> I’m yatil on IRC.




--

Eric Eggert, Web Accessibility Specialist
WAI-ACT Project

I’m yatil on IRC.