Moving to XML

• HTML was created as an application of SGML - the Standard Generalized Markup Language (ISO 8879:1986)

• XML is a descendant of SGML, which is easier to implement

• XML requires you to:

  • make tags case-sensitive
  • include end tags e.g. </p> and </li>
  • add a / to empty tags, e.g. <br /> and <hr />
  • quote all attribute values, e.g. <img src="karen.jpg" />
  
  

• These make it practical to parse well-formed XML without a priori knowledge of the tags

• XHTML uses lower-case for tags and attributes

• Old browsers can render XHTML 1.0 provided you follow simple guidelines