title: Running multiple scripts on async defer problems
body: <p>I have 2 scripts which should be run with async defer. but the problem is that the 2nd script relies on the first one. <code>js-map-label.js</code> needs to be run only after <code>googleapis</code> has been loaded and running. it works 80% of the time with this setup. but sometimes it wouldn't run, so I had to refresh over and over till the <code>js-map-label.js</code> runs. Is there any way to fix this?</p>
  
  <p>I have these scripts in this order:</p>
  
  <pre><code>    ...
      &lt;script src="https://maps.googleapis.com/maps/api/js?key=__MY_KEY_HERE__...." async defer&gt;&lt;/script&gt;
      &lt;script src="/static/js/js-map-label.js" async defer&gt;&lt;/script&gt;
      ...
  &lt;/body&gt;
  </code></pre>
  
  <p>It would sometimes raise this error:</p>
  
  <pre><code>js-map-label.js:13 Uncaught ReferenceError: google is not defined
      at js-map-label.js:13
      at js-map-label.js:16
  </code></pre>