Stylesheets do not only block rendering but also JavaScript execution

Today I learned that when you have the following snippet...

<link rel="stylesheet" href="app.css" />

<script>
  var script = document.createElement('script');
  script.src = "analytics.js";
  document.getElementsByTagName('head')[0].appendChild(script);
</script>

... the inline JavaScript code snippet won't be executed before the stylesheet is loaded. It seems strange at first, but when you think about it, this behaviour makes a lot of sense because it may be that the JavaScript will access some element styles.

All kudos to Harry Roberts who described this behavior in an excellent article. Thanks Harry!