Notation Declaration

Defines the helper application to deal with the binary file

  <!ELEMENT banner EMPTY>
  <!ATTLIST banner image ENTITY #REQUIRED>
  <!ENTITY unionjack.png SYSTEM "http://www.uk.gov/unionjack.png NDATA png>
  <!NOTATION png SYSTEM "file:///C:/Program Files/Internet Explorer/PNGplugin.exe">

So when the following appears:

  <banner image="unionjack.png"/>

• the browser knows that image is a valid attribute;
• when the attribute value is unionjack.png the file is to be found at http://www.uk.gov/unionjack.png;
• it is binary data of type png;
• binary data of type png is handled by the program PNGplugin.exe