- From: Michael(tm) Smith <mike@w3.org>
- Date: Wed, 11 Feb 2009 16:22:13 +0900
- To: Elliotte Rusty Harold <elharo@metalab.unc.edu>
- Cc: "Henry S. Thompson" <ht@inf.ed.ac.uk>, Anne van Kesteren <annevk@opera.com>, David Orchard <orchard@pacificspirit.com>, Henri Sivonen <hsivonen@iki.fi>, www-tag@w3.org
Elliotte Rusty Harold <elharo@metalab.unc.edu>, 2009-02-10 17:32 -0800: > On this point, I have to call B.S. again. That a document is served as > text/html does not make it HTML. Much less does it make it not XML. If a > document satisfies the BNF grammar and the various well-formedness > constraints, That's exactly the point. Much if not most of the XHTML content being served as text/html on the Web does not satisfy XML well-formedness constraints. The only reason it doesn't become completely unusable in browsers is that it gets processed by HTML parsers in browsers instead of by their XML parsers. If it were to be served with a proper XML MIME type instead -- or if browsers were to do sniffing for the XHTML doctype or namespace and actually parse it as XML instead of as HTML -- it would fail to remain accessible on the Web. > it is XML, whatever you call it. I guess some might call it broken XML. > It may also be HTML, and perhaps other things as well. > > The MIME type is not normative. That someone has labeled a document as one > thing or another does not make it that thing. That may be the general case. In this specific case, serving a document on the Web with the text/html MIME type makes it one very definite thing: A document that will get processed as HTML by browsers, not as XML. It also makes it a document that should (if the producer of the document wants to ensure that browsers can actually process it as expected, without needing to fall back to error correction) follow HTML-specific constraints. That means the producers of such documents would need to follow some constraints that XML tools are not able to check; for example, they need to make sure they don't use self-closing tags for elements that have required end tags, such as <script> or <a name> instances. And they need to make sure that any <script> or <style> element content follows HTML constraints, not XML/XHTML constraints. > If people are serving well-formed XML, it is likely they do so because they > find it useful to do so, whatever MIME type happens to be assigned. I don't think that's necessarily likely at all. They may have just copied an XHTML document from somewhere else and used it as a template for their own content. Or they may be using an editor that by default produces XHTML-namespaced documents with an XHTML doctype. Or they may be attempting to produce XHTML (using an XHTML doctype and namespace, quoting attribute values, using self-closing-tag syntax on empty elements) just because they've heard or been taught that's what they should be doing, without having any real understanding of the supposed benefits of doing it. --Mike -- Michael(tm) Smith http://people.w3.org/mike/
Received on Wednesday, 11 February 2009 07:22:26 UTC