XHTML 1.0 is a Rec

The Abstract says:

  This specification defines XHTML 1.0, a reformulation of HTML 4 as
  an XML 1.0 application, [...] Compatibility with existing HTML user
  agents is possible by following a small set of guidelines.

The interesting thing about the reformulation is the difference in
user agent conformance requirements with respect to wayward input.

 [W3C/Rec: HTML 4.0, 1998/04/28]
 [W3C/Rec: HTML 4.01, 1999/12/24]

 B.1 Notes on invalid documents

   This specification does not define how conforming user agents
   handle general error conditions, including how user agents behave
   when they encounter elements, attributes, attribute values, or
   entities not specified in this document.

   However, to facilitate experimentation and interoperability
   between implementations of various versions of HTML, we recommend
   the following behavior:

     * If a user agent encounters an element it does not recognize,
       it should try to render the element's content.
     * If a user agent encounters an attribute it does not recognize,
       it should ignore the entire attribute specification (i.e., the
        attribute and its value).
     * If a user agent encounters an attribute value it doesn't
       recognize, it should use the default attribute value.
     * If it encounters an undeclared entity, the entity should be
       treated as character data.

   We also recommend that user agents provide support for notifying
   the user of such errors.

 [W3C/PR: XHTML 1.0, 2000/01/26]

 3.2 User Agent Conformance

   A conforming user agent must meet all of the following criteria:

   1. In order to be consistent with the XML 1.0 Recommendation [XML],
      the user agent must parse and evaluate an XHTML document for
      well-formedness. If the user agent claims to be a validating
      user agent, it must also validate documents against their
      referenced DTDs according to [XML].
   4. If a user agent encounters an element it does not recognize, it
      must render the element's content.
   5. If a user agent encounters an attribute it does not recognize,
      it must ignore the entire attribute specification (i.e., the
      attribute and its value).
   6. If a user agent encounters an attribute value it doesn't
      recognize, it must use the default attribute value.


All those "should"s have turned into "must"s.

This is a very bad "trend" for XHTML 1.1 to follow, as the WD suggests
it will.


Arjun

Received on Thursday, 27 January 2000 20:18:34 UTC