W3C home > Mailing lists > Public > www-validator@w3.org > November 2004

Re: Color in pages

From: Bjoern Hoehrmann <derhoermi@gmx.net>
Date: Mon, 22 Nov 2004 04:34:00 +0100
To: Jon Ribbens <jon+www-validator@unequivocal.co.uk>
Cc: www-validator@w3.org
Message-ID: <41a15bcb.4560953@smtp.bjoern.hoehrmann.de>

* Jon Ribbens wrote:
>"Jukka K. Korpela" <jkorpela@cs.tut.fi> wrote:
>> That's because it is valid. Validation is formal, and it only covers those
>> aspects of markup that are defined at the formal level (basically, in the
>> DTD); see http://www.cs.tut.fi/~jkorpela/html/validation.html for a longer
>> explanation.
>I must admit I don't entirely get this. Why does the word "valid" have
>such a strange meaning when applied to HTML?

If you check the various HTML specifications you will find that it does
not have such a strange meaning, the HTML 4.01 Recommendation notes the

  Beware that such validation, although useful and highly recommended,
  does not guarantee that a document fully conforms to the HTML 4
  specification. This is because an SGML parser relies solely on the
  given SGML DTD which does not express all aspects of a valid HTML 4
  document. Specifically, an SGML parser ensures that the syntax, the
  structure, the list of elements, and their attributes are valid. But
  for instance, it cannot catch errors such as setting the {width}
  attribute of an { IMG} element to an invalid value (i.e., "foo" or
  "12.5"). Although the specification restricts the value for this
  attribute to an "integer representing a length in pixels," the DTD
  only defines it to be {CDATA}, which actually allows any value. Only
  a specialized program could capture the complete specification of
  HTML 4.

  Nevertheless, this type of validation is still highly recommended
  since it permits the detection of a large set of errors that make
  documents invalid.

The interpretation you cite assumes that the various SGML DTDs express
all aspects of a valid HTML 4 document which obviously contradicts the
Received on Monday, 22 November 2004 03:34:31 UTC

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