Does your website have several files that are included? Do you not want to have them output anything if they are addressed directly? Here is a very simple script to do that:

<?php
function amIincluded() {
  $requestedURL = parse_url($_SERVER['REQUEST_URI']);
  if(basename($requestedURL['path']) != basename(__FILE__))
   return true;
  return false;
}
?>

This amIincluded function gets the address of the page in your browser. Then it parses that into its parts and gets the filename. If that filename is the same as the filename of the file, it returns true otherwise it returns false.

A sample usage of this is:

<?php
if(amIincluded()) {
echo 'Included';
} else {
echo 'Not Included';
}
?>