- From: Charles McCathieNevile <chaals@opera.com>
- Date: Thu, 12 Feb 2009 10:09:22 +0100
- To: "Leif Halvard Silli" <lhs@malform.no>
- Cc: "HTML WG" <public-html@w3.org>
On Wed, 11 Feb 2009 17:41:03 +0100, Leif Halvard Silli <lhs@malform.no> wrote: > Charles McCathieNevile 2009-02-11 09.13: >> Wed, 11 Feb 2009 00:41:07 +0100, Leif Halvard Silli: >>> 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. >> Actually, I think Ian's machine-checkable exceptions are reasonable >> candidates for "conformant". > > "Actually", you say. But which definition of "conformant" do you use > today? If it is "conformant but not recommended", then it is > "conformant". Why should it be /recommended/ to do so? The draft in fact > says that it is /not/ recommended - authors should take steps to try to > instead produce valid @alt content. How can the validator inform the > author about this unless it tells him that this is not recommended? By "reasonable candidates" I mean that I think they are not crazy ideas (ergo reasonable) but that they need further consideration, at least by me to form a solid opinion, hence candidates. I am not certain whether or not these alternate approaches should be *recommended*. Thinking out loud: It makes sense to me, in the cases where something else serves as the alternative, to *require* alt="", i.e. there is an alt attribute, and it is empty. But since there is a caption elsewhere you should check that text like you would the content of an alt attribute. In these machine-checkable cases where there is *no* alt, it may make sense to make them conformant but not recommended. It may also make sense to make them non-conformant, and to require alt, with anything other than alt="" being not recommended, parallel to the recommendation not to have alt produced by default. I haven't thoroughly considered the use cases in this context (e.g. the famous Flickr thing) so I am not yet certain of this. ... > Firstly, if - when the @alt should be non-empty - it is a more serious > to leave it empty than to delete it entirely, then what do you propose > that the draft and validators should do with that? > > I suggested one method that would catch /some/ such errors, namely to > send a negative signal if an <IMG> has both an empty @alt and a > non-empty @title. This seems like the logical consequence of making > validators look at @title in order to decide if non-present @alt is > conformant. Yeah. Thinking through this case, I am not sure that @title is a good candidate alternative for @alt. In my understanding over the last ten years (and consequently my teaching and writing over that period, which is not the most influential but nor is it non-existent) they have distinct purposes - one is a direct alternative, the other is semi-visible (not inline by default, but available) supplementary information, as per the current draft of HTML5[1]. I realise that they are not always used that way (just by looking at what people who start working at Opera do with them) but I am not sure about the relative frequency of various usage. > It would allow authors to improve the <IMG> by either deleting the @alt > (if that is concidered better) or filling it with content. Or even > remove the @title, as well. > > What do you think of this? > > Secondly, aren't we mixing up repair issues and semantics if we say that > to delete the @alt is better than to leave it empty? No, the semantics of the two cases are different: alt="" has a semantic meaning of "move along, nothing to see here" (with apologies to graphic designers who put in a lot of work to decorate pages so they are pleasant to look at for most of us), while the absence of alt suggests that the semantics are completely unknown - similar to a paragraph written in a made-up language nobody understands, so you have no way of knowing if it is just filler text to take up space (like "lorem ipsum dolor sit amet...") or a very incisive and witty comment. > When will it break the Web to repair <img>-s with a non-empty @title > both when @alt is empty and @alt is un-present? Assuming you use them in the way that I understand, neither case would break the web but nor would they be a proper repair. [1] http://dev.w3.org/html5/spec/Overview.html#alt especially at section 4.8.2.1.5 cheers Chaals -- Charles McCathieNevile Opera Software, Standards Group je parle français -- hablo español -- jeg lærer norsk http://my.opera.com/chaals Try Opera: http://www.opera.com
Received on Thursday, 12 February 2009 09:10:10 UTC