Introducing XML

₃₀

A meta-language.

Allows arbitrary sets of elements

<document> 
  <title> 
    <bf> ... </bf> 
    <it> ... </it> 
  </title> 
  <body> ... </body> 
</document>

Requires well formed documents

<p> 
   <b>...</b> 
   <hr/> 
</p>

<p> 
   <b>...</b> 
   <hr>