title: Async script not caching in chrome
body: <p>So I this issue that I have a big javascript file that I want to cache. The problem is that for some reason chrome just wont cache the file FF works perfectly.</p>
  
  <p>Response headers </p>
  
  <pre><code>Cache-Control:max-age=300
  Connection:Keep-Alive
  Content-Type:application/javascript
  Date:Wed, 15 Nov 2017 07:34:18 GMT
  Expires:Wed, 15 Nov 2017 07:39:19
  Keep-Alive:timeout=5, max=97
  Pragma:cache
  Server:Apache/2.4.25 (Unix) PHP/5.6.30 LibreSSL/2.2.7
  Transfer-Encoding:chunked
  User-Cache-Control:max-age=300
  X-Powered-By:PHP/5.6.30
  </code></pre>
  
  <p>request headers</p>
  
  <pre><code> Accept:*/*
   Accept-Encoding:gzip, deflate, br
   Accept-Language:fi-FI,fi;q=0.8,en-US;q=0.6,en;q=0.4
   Connection:keep-alive
  </code></pre>
  
  <p>Script is called from header with </p>
  
  <p><code>&lt;script async src='/resource'&gt;&lt;/script&gt;</code></p>
  
  <p>Any ideas what could be the issue?</p>