Common.js
From ZDN User Guide
<script async src="https://www.googletagmanager.com/gtag/js?id=G-99ZFTN524N"></script> <script>
window.dataLayer = window.dataLayer || [];
function gtag(){dataLayer.push(arguments);}
gtag('js', new Date());
gtag('config', 'G-99ZFTN524N');
</script>
