responsive ad unit with revive ad server

4ffd0b928327fe8b8edcadb94bedc2dc.html

<div id="revive-responsive-top" style="display: block; text-align: center;">
  <script type="text/javascript">
 
    adUnit   = document.getElementById("revive-responsive-top");
    adWidth  = adUnit.offsetWidth;
 
    if ( adWidth >= 728 ) {
      /* Leaderboard 728x90 */
       adUnit.innerHTML = '<ins data-revive-zoneid="3" data-revive-id="4689b54ec658f530f3250f4124e7f1ea"></ins>';
    } else {
      /* Mobile Banner 320x50 */
      adUnit.innerHTML = '<ins data-revive-zoneid="5" data-revive-id="4689b54ec658f530f3250f4124e7f1ea"></ins>';
    } 
   
  </script>
  <script async src="//revive.example.com/www/delivery/asyncjs.php"></script>
</div>

can use without direct link to parent id
var scriptTag = document.getElementsByTagName('script');
scriptTag = scriptTag[scriptTag.length - 1];
var adUnit = scriptTag.parentNode;