- From: Christophe Strobbe <christophe.strobbe@esat.kuleuven.be>
- Date: Thu, 11 May 2006 22:53:27 +0200
- To: public-wai-ert@w3.org
Carlos Velasco asked <blockquote> what happens when a delivery unit (...) has a CSS like http://example.com/css/example.css? It is in scope or not? </blockquote> Christophe Strobbe responded: <blockquote> A stylesheet is not a Web unit but an "authored unit", and when it is "intended to be used as a part of another authored unit", it is an "authored component" (http://www.w3.org/TR/WCAG20/appendixA.html#authored-componentdef). Conformance claims apply to Web units, not to authored units. So if a Web unit within the scope of your conformance claim uses a CSS that is outside the scope of your conformance claim, my understanding is that the conformance claim applies to the Web unit *with* the CSS (but not to the CSS in isolation). </blockquote> Then Johannes Koch wrote back: <blockquote> Let's make it a little more complicated :-) As Carlos Iglesias quoted, a Web Unit is "A collection of information, consisting of one or more resources, intended to be rendered together, and identified by a single Uniform Resource Identifier (such as URLs)". Let's consider an HTML document with various linked stylesheets, one for screen, one for print, one for projection, ... They are not intended to be rendered (all) together. So which CSS file belongs to the Web Unit identified by the HTML document's URL? Or are there different Web Units for each CSS file together with the HTML document. But how do I identify them? The HTML document has only one URL. </blockquote> You can't make assumptions about how the type of user agent that will be used to render the HTML document: on a screen, through projection, on a refreshable braille display, with speech synthesis, ... So if the HTML document, say 'home.htm', has stylesheets for each of these media types, the following would all count as Web units: - home.htm with the CSS for 'screen', - home.htm with the CSS for 'projection', - home.htm with the CSS for 'braille', - home.htm with the CSS for 'aural', - ... So the question becomes: if you have a conformance claim that has the above 'home.htm' in its scope, does the conformance claim cover each of the above examples? Since you can't make assumptions about the user agent, I think the answer is yes. (How you represent this in EARL is another matter.) I don't think it makes sense to define the Web unit as home.htm + screen.css + projection.css + braille.css, ... Come to think of it: if you use an object element with one or more fallbacks nested inside it (see the example slightly below http://www.w3.org/TR/1999/REC-html401-19991224/struct/objects.html#idx-object-5), I think the Web unit you claim conformance for is the HTML document with the outermost object element (with the TheEarth.py applet). Now let us look at a few scenarios. 1. Let us assume that Python applets are not in the baseline and that there is a fallback for each Python applet using a technology within the baseline, then the conformance claim applies to the fallback (and the Python applets must not interfere with the content). I don't know if EARL can take baselines into account (I'm too tired to check now). Maybe a "Baseline Description Language" would be useful? 2. Alternatively, let us assume that Python applets are in the baseline and there is a fallback for each Python applet using another technology within the baseline. What happens if the Python applet cannot be retrieved from the server, so that the fallback is used instead. How does this affect the conformance claim? Can EARL make statements about the HTML document + fallback object? 3. Let us assume that Python applets are in the baseline and there is a fallback for each Python applet using another technology outside the baseline. (I think this is not very logical, but it is possible.) What happens if the Python applet cannot be retrieved from the server, so that the fallback is used instead. How does this affect the conformance claim? (To be continued...) Regards, Christophe -- Christophe Strobbe K.U.Leuven - Departement of Electrical Engineering - Research Group on Document Architectures Kasteelpark Arenberg 10 - 3001 Leuven-Heverlee - BELGIUM tel: +32 16 32 85 51 http://www.docarch.be/ Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm
Received on Thursday, 11 May 2006 20:53:39 UTC