HTML - XHTML - XML

• HTML4 - A well established standard with Millions of pages in existence

• XHTML - A middle ground that allows HTML pages to be made compliant with the XML standard.

• XML - A new standard that is NOT backwardly compatible with earlier browsers or with HTML code. (The PS-2 or Betamax of HTML)

• HTML5 – After realizing the move to XML would never happen W3C backtracked and implemented HTML5, incorporating more css into the design