title: Is async ever better than defer?
body: <p>The way I understand it, scripts should be <code>defer</code>ed rather than <code>async</code>ed because that way parsing doesn't need to stop to execute them (I am going by <a href="http://www.growingwiththeweb.com/2014/02/async-vs-defer-attributes.html" rel="noreferrer">these graphs</a>). If parsing has to stop, that means the page content takes longer to show up right? If that's the case, why would <code>async</code> ever be better than <code>defer</code>?</p>
  
  <p>Example: I am using Google reCAPTCHA on my site. Google has asked me to insert the script just before my closing <code>&lt;/head&gt;</code> tag:</p>
  
  <pre><code>    &lt;script src='https://www.google.com/recaptcha/api.js'&gt;&lt;/script&gt;
  &lt;/head&gt;
  </code></pre>
  
  <p>Why would this script need to execute before the page finishes loading? Shouldn't I <code>defer</code> it?</p>