Yes, the W3C recommends using XHTML which is ‘a reformulation of HTML 4 in XML
1.0’. This specification defines HTML as an XML application, and provides three
DTDs corresponding to the ones defined by HTML 4.* (Strict, Transitional, and
The semantics of the elements and their attributes are as defined
in the W3C Recommendation for HTML 4. These semantics provide the foundation for
future extensibility of XHTML. Compatibility with existing HTML browsers is
possible by following a small set of guidelines (see the W3C site).