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Re: "downplayed errors"

From: Leif Halvard Silli <lhs@malform.no>
Date: Wed, 11 Feb 2009 00:41:07 +0100
Message-ID: <49921093.4000704@malform.no>
To: Robert J Burns <rob@robburns.com>
CC: Ian Hickson <ian@hixie.ch>, Charles McCathieNevile <chaals@opera.com>, Henri Sivonen <hsivonen@iki.fi>, HTML WG <public-html@w3.org>

Robert J Burns 2009-02-10 18.37:
> On Feb 9, 2009, at 8:32 PM, Ian Hickson wrote:
>> On Tue, 10 Feb 2009, Charles McCathieNevile wrote:
>>> For example, I think we could get consensus that img with 
>>> no al attribute is "conformant but not recommended". I 
>>> don't think we will get consensus that img with no alt is 
>>> conformant and recommended, and I am dubious about 
>>> consensus that it is non-conformant.
>> As far as I can tell we already have consensus on alt="" 
>> being required. (With one or two exceptions, the spec 
>> requires alt="" to be present. The exceptions are 
>> machine-checkable.)
> Up to your first sentence I think we agree. Though I might have
>  gone so far to say we have consensus since I felt there were 
> some objections to alt='' being required.

It is worth trying to understand Ian vs. Charles. Both agree that 
HTML 5 documents entirely free from alt attributes could deserve 
the W3 Validator's "Valid" badge - depending on so and so.

However, according to Charles, lack of @alt becomes a 'downplayed 
error' ('conformant but not recommended'). It is unclear whether 
Charles sees *any* lack of alt as 'conforming/not recommended' or 
if he limits conformances to Ian's machine-checkable exceptions.

While Ian, OTOH, wants the machine-checkable exceptions (namely 
IMG@title with content, <figure> with caption or figure like 
<section>-s) to be singled out as conforming. While any other lack 
of @alt should be considered non-conforming.

Of these, I prefer the compromise, namely that Ian's exceptions 
get validated as 'conformant but not recommended'. Such a stamp 
seems to be in line with the strong advice in the draft against - 
even in these exception cases - ever dropping @alt.

To avoid that lack of alt mechanically gets stamped as conforming 
(or non-conforming), but instead evaluate the context before 
judging, should promote better understanding amongst authors, as 
it requires them to think instead of acting mechanically. Thus, I 
applaude the efforts for defining a level of machine-checkability!

However, I would like this to also be applied to those times when 
@alt *has* content. For instance if both @title and @alt has the 
*same* content, then one can be reasonably certain that either 
@title or @alt is used wrong. Same content in @alt and @title 
should therefore be considered 'conformant but not recommended'.

And likewise I think that if @title has some content, while @alt 
is empty, then this too needs to be 'conformant but not 
recommended'. It is right to consider empty alt and lack of alt as 
semantically equal. Lack of alt or empty alt is the same when the 
reality is that the alt should have had content. The only 
difference is that the annoyance level (a fact that perhaps speaks 
to the advantage of no alt - in some cases.)

Thus theese are the same, and with the same machine-checkability:

<img alt="" title="Photographer: Helmut Newton." src="src" >
<img        title="Photographer: Helmut Newton." src="src" >
Leif Halvard Silli
Received on Tuesday, 10 February 2009 23:41:59 UTC

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