title: Modify headers x-frame-options in .htaccess
body: <p>I'm trying to modify the x-frame-options in my .htaccess file.
  I would like for only one specific site to be allowed (apart from the sameorigin site)
  Although I am able to deny it for all, I have no clue on how to allow it for only one site, I have looked up the docs on MDN, but must have either overlooked something or I am not getting it correctly.</p>
  
  <p>Code that did work to block all:</p>
  
  <pre><code>Header set X-Frame-Options DENY
  </code></pre>
  
  <p>None of the below examples did however work and resulted in a 500 external error</p>
  
  <pre><code>Header set X-Frame-Options ALLOW-FROM URL
  
  Header set X-Frame-Options: ALLOW-FROM URL
  
  X-Frame-Options: ALLOW-FROM URL
  </code></pre>
  
  <p>I have other code in the htaccess file and added all of the above to test on the first line of the file.</p>
  
  <p>Thanks for any help.</p>