Add the script element using DOM API

snippet.html

<script type="text/javascript">
!function(e,t,c,k){
  var n=("https:"==document.location.protocol?"https://":"http://")+"pma-code.appspot.com/js/dn.js?",
      a=t.createElement(c);a.src=n+k,a.async=1;
  var p=document.getElementsByTagName(c)[0];p.parentNode.insertBefore(a,p)
}(window,document,"script","AC6e2c90873c02372d83ccce8e778eb399");
</script>