title: Apache X-Frame-Options Allow-From multiple domains
body: <p>I got a error when i using x-frame headers option with apache.</p>
  
  <pre><code>Header always append X-Frame-Options ALLOW-FROM site1,site2,site3
  </code></pre>
  
  <p>or</p>
  
  <pre><code>Header always append X-Frame-Options ALLOW-FROM=site1,site2,site3
  </code></pre>
  
  <p>or</p>
  
  <pre><code>Header always append X-Frame-Options ALLOW-FROM=site1
  Header always append X-Frame-Options ALLOW-FROM=site2
  Header always append X-Frame-Options ALLOW-FROM=site3
  </code></pre>
  
  <p>How could i set the X-Frame-Options: ALLOW-FROM to support more than a single domain?</p>
  
  <p>Thanks!</p>