title: How to detect if a user leaves a page in PHP
body: <p>There is this function which i want to execute in case the user leaves a particular page. This function will basically change all of the data within a certain column in my database. So in case the user leaves this page, i want this function to be performed by the system. Is there a way to detect if the user already left the page. </p>
  
  <p>Thanks!</p>