Async script loading

dynamic-load.html

<!-- dynamic async loading -->
<script type="text/javascript">
  (function(src){
    var po = document.createEkement('script');
    po.type = 'text/javascript';
    po.async = true; //VERY IMPORTANT!!! 
    po.src = src;
    var s = document.getElementsBytagName('script')[0];
    s.parentNode.insertBefore(po, s);
  })("https://apis.google.com/js/plusone.js");
</script>

static-load.html

<!-- static loading: sync vs. defer vs async -->
<script src="//example.com/sync.js"></script>
<script src="//example.com/defer.js" defer></script>
<script src="//example.com/asyns.js" async></script>