XHTML 1.0: The Extensible HyperText Markup Language (Second Edition)1. What is XHTML? 1.1. What is HTML 4? 1.2. What is XML? 1.3. Why the need for XHTML? 2. Definitions 2.1. Terminology 2.2. General Terms 3. Normative Definition of XHTML 1.0 3.1. Document Conformance 3.1.1. Strictly Conforming Documents 3.1.2. Using XHTML with other namespaces 3.2. User Agent Conformance 4. Differences with HTML 4 4.1. Documents must be well-formed 4.2. Element and attribute names
The W3C Markup Validation Service
