XHTML 1.0

• Semantically equivalent to HTML 4.01
• Has 'strict', 'frameset', and 'transitional' versions
• Uses XML syntax
• Designed to make use of "quirks" of existing browsers
• Use a small number of guidelines, eg:
  • all elements must be closed (eg, <p>...</p>)
  • all attribute values must be quoted
  • use space before "/" of empty elements: <hr />
  • etc
• Documents can be served both as XML and HTML