title: How to set custom headers in PHP
body: <p>JAVA developer send me data in headers. I take it this way</p>
  
  <pre><code>$_SESSION["HTTP_COUNTRYNAME"];
  </code></pre>
  
  <p>How to make response back with headers?  It tried <code>header("countryname: USA");</code> but php <code>function headers_list</code> doesn't show it.</p>