- From: Robert Burns <rob@robburns.com>
- Date: Sat, 18 Aug 2007 20:21:21 -0500
- To: Philip Taylor <philip@zaynar.demon.co.uk>
- Cc: public-html WG <public-html@w3.org>
Hi Philip, On Aug 18, 2007, at 6:47 PM, Philip Taylor wrote: > > Robert Burns wrote: >> [...] In an HTMl5 conforming document embedrel would be required. >> In other words: "authors MUST include the @embedrel attribute on >> any embedded content element". [...] >> So this proposal also makes @alt no longer a required attribute. >> Instead it makes @embedrel a required attribute on all embedded >> content (non-text media) elements. > > One problem with adding new required attributes is that a large > amount of conforming HTML4 content will be made non-conforming > HTML5, and can not be trivially converted into conforming HTML5. First, I'd say that there's no need for authors to go turn all of their HTML4 content into HTML5. That should be driven by the need to take advantage of HTML5 features. I don't think it will be a good idea for us to make authors think they're going to gain something simply by changing their declaration from one non-quirks mode doctype to the HTML5 non-quirks mode doctype. Converting to HTML5 therefore means an author wants to take advantage of HTML5 features. As for trivially converting, I think it could be done rather easily. Authors are typically fairly familiar with their own authored content. They know whether their @alt values are meaningful or whether they added them to satisfy the validator. If its the former, then the IMG element's simply need to have alt='seefallback' added. If its the latter, then they need alt='missing' (optionally they can then strip the meaningless alt tags). If the author know they used alt='' to indicate decorative images, then embedrel='decorative' can be added to the IMG elements. There may be some need for human interaction here, but for large groups of documents or entire sites created by the same authors its simply a matter of adding 'seefallback', 'missing', or 'decorative' to the IMG elements. Some of those 'missing' keywords may also qualify for 'seecontext', and that would require some human intervention, but nothing requires authors to do that.. Also the proposal has backwards compatibility built in. By not having this attribute set, an HTML5 conforming UA treats the embedrel attribute as having a keyword 'undefined'. This lets the HTML5 conforming UA know that the @alt attribute may not be used as precisely as it is in HTML5. > As I understand your proposal, every <img> on a site would have to > (at minimum) be converted into <img embedrel="missing"> - depending > on how the site is produced, that would require changes to static > HTML files, HTML template files, HTML in print statements spread > throughout script code, fragments of HTML in databases; and most of > that work would have to be done manually rather than using > automatic conversion tools. The conversions would only be required for those wanting to pass HTML5 conformance checking requirements. Sites could continue to serve HTML4 without any problems. Of those situations you list, only the databsse pages seems to me to be a concern. There, the HTML4 fragments in the database would be combined with HTML5 templates or generated HTML5 to create a hybrid of content where @embedrel is set on some elements and not others. However, no one is typically runs these types of pages through a conformance checker anyway. I If they did, they would learn that their old HTML4 needed @embedrel attributes to be conforming HTML5. I don't really think that's a major problem compared to the problem we're trying to solve here (creating some sort of sanity around alt values). > Currently, many conforming HTML4 documents can be made into > conforming HTML5 by just using the appropriate doctype. Requiring > authors to make all the above changes to use a new required > attribute, especially when it provides them with no value in any > current or future browser, seems likely to discourage many > standards-aware authors from ever wanting to migrate to HTML5. Why do we want authors to change their doctype declarations to become conforming HTML5? Especially when that provides no value in any current or future browser? Adding the @embedrel attribute provides benefits. That's why I'm proposing it. Certainly batch converting all content by adding embedrel='missing' to every IMG element just to claim HTML5 conformance would be a bad idea. The point of converting the document in this case would be to add the richer information included in the embedrel attribute. Only then would this author or site gain any benefits from HTMl5 (not by just changing its doctype declaration). Adding sectioning elements or adding VIDEO, AUDIO, CANVAS, etc. all requires non-trivial author intervention. Sure, they're not required, but automating this task could be fairly simple to differentiate 'missing' from 'seefallback' from 'decorative'. Further differentiating 'seecontext' and 'icon' may require further author scrutiny, but it will benefit users. And just to repeat the proposal still works when @embedrel is absent since the value imputed by UAs will be either 'missing' if @alt is missing, 'decorative' for alt='' and 'undefined' for alt='<string length greater than 0'>. Even that will be at least as useful for users as the current situation and the current draft proposal. Take care, Rob
Received on Sunday, 19 August 2007 01:21:33 UTC