How to prevent direct access to load content

How to prevent direct access to load content

I have a php page that uses the a load request (see bow). I would like to prevent people viewing the content directly. I understand I could possibly check the header (also see below) but this apparently can be easily hoodwinked. Any suggestions?

Header check;
  2. </php
  3. function is_xhr() {
  4.   return @ $_SERVER[ 'HTTP_X_REQUESTED_WITH' ] === 'XMLHttpRequest';
  5. }
  6. if( is_xhr() ){
  7. // respond to Ajax request
  8. } else {
  9. // respond to normal request
  10. }
  11. ?> 
The load request;
  1. $('.mydivcontainer').load('myContentFile.php');