title: Possible to add value to an existing cookie in PHP?
body: <p>I have a classifieds site, and on the main page I want the last visited ads by the existing user to show up.</p>
  
  <p>How would I do this?</p>
  
  <p>Basically, it has to be something like this:</p>
  
  <ol>
  <li>User clicks on an ad.</li>
  <li>The ad ID gets saved in a cookie.</li>
  <li>Then, when clicking on another ad, that ad ID gets saved also.</li>
  <li>Then, whenever visiting the main page, those ads will be displayed by fetching the AD ID:s from the cookie.</li>
  </ol>
  
  <p>Is it even possible to add values to an existing cookie ?</p>