- From: Nir Dagan <nir@nirdagan.com>
- Date: Wed, 18 Nov 1998 01:08:32 GMT
- To: w3c-wai-gl@w3.org
Al says: "Where is the contradiction? CLASS was put in HTML4.0 specifically to be an extension mechanism, to support semantics not covered in the DTD. This is just the tip of the iceberg. In XML all semantics is after the fact, except for one very abstract inclusion tree and cross-reference via X-pointer." Class is an extention mechanism for author defined semantics. Class is not a mechanism that allows the W3C to extend HTML in a way that breaks existing documents. HTML spec. says authors can define any class for any purpose. Since the class attribute exists in an experimental HTML version published by the W3C shortly after CSS1 became recommendation, we can safely assume that every class name that can you think of has been used by many people for completely different author defined semantics. I may have used class=nav to indicate a poem. If WAI decides that class=nav is defaulted by browsers to {speak:none} it is exactly the same as saying that from now on H1 should be defaulted by browsers to {display:table}, as getting all my poems not to be read is more or less as bad as displaying all my headings as tables. Any class name may have pre defined semantics in *existing particular documents*. Authors who believed the W3C, assumed that browsers and users do not and never will set style rules for the author defined classes. On the other hand if we say that the new HTML element NAVBAR may be defaulted to display:none in browsers, it is a problem of the author if he extended W3C recommendations to include this element to describe poems. This is because HTML states that authors should not extend the DTD by declaring new elements. In regard to XML, its advantage is the you can create documents in a "modular" way using some *prespecified* semantics of different tag-sets (MathML, vector graphics, etc.), as well as some of the author's own, if needed. The fact that an author can use author defined set of tags without any universal meaning is useless because anything you can do with XML + stylesheets you can do with HTML + stylesheets using only the SPAN element with the class attribute. (as the SPAN element and class attribute have no predefined semantics). The advantage of XML is not that WAI says that I have to rewrite my website because the WAI decided that class=nav is a navigation bar after I, following HTML4.0, decided that it is poem. In this sense if WAI says that browsers should safely assume that class=nav is a navigation bar, and skip them when spoken, WAI recommendations are backward imcompatible with HTML4.0, which allows class=nav to be anything that the author wanted, including a poem. Nir Dagan, Ph.D. http://www.nirdagan.com mailto:nir@nirdagan.com "There is nothing quite so practical as a good theory." -- A. Einstein
Received on Tuesday, 17 November 1998 11:07:26 UTC