title: Why is my php page still caching after taking the appropriate measures?
body: <p>I have a PHP page which fetches prices from an API and I'd like it to not cache anything as I've set the page to reload every 15 seconds <code>&lt;meta http-equiv="refresh" content="15"&gt;</code>so the prices can be updated. </p>
  
  <p>I've added the following code to my index.php file, but it still seems to cache, when I open up Google Chrome in incognito mode, (sometimes) I see different numbers.</p>
  
  <p>In<code>&lt;body&gt;</code> I have: </p>
  
  <pre><code>&lt;?php
  $ts = gmdate("D, d M Y H:i:s") . " GMT";
  header("Expires: $ts");
  header("Last-Modified: $ts");
  header("Pragma: no-cache");
  header("Cache-Control: no-cache, must-revalidate");
  ?&gt;
  </code></pre>
  
  <p>Also:</p>
  
  <pre><code>&lt;?php
  header("Cache-Control: no-store, no-cache, must-revalidate, max-age=0");
  header("Cache-Control: post-check=0, pre-check=0", false);
  header("Pragma: no-cache");
  ?&gt;
  </code></pre>
  
  <p>I'm also using this: <code>&lt;html manifest="manifest.appcache"&gt;</code>at the start of my code, which contains the following: </p>
  
  <pre><code>CACHE MANIFEST
  
  # Cache manifest version 1.0
  
  # no cache
  
  NETWORK:
  * 
  </code></pre>
  
  <p>BTW, isn't the first block of PHP code doing exactly what the second block of PHP code is doing? Is it necessary to have them both? Also, isn't the purpose of the manifest.appcache defeated when I try to do with php?</p>