title: How to start a PHP background process on server side when user fetches a page?
body: <p>I have no experience with PHP and I am wondering if this is possible:</p>
  
  <p>I want to start a background PHP process when a user fetches a page. This process would check whether some delay has expired (for example a timestamp in a file) and execute accordingly. The page can 'return' before the process has finished its execution.</p>
  
  <p>Is this realistic and if yes, how should I proceed? What would be the code to launch the process when the page is fetched? Thanks.</p>