JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//cdnjs.cloudflare.com/ajax/libs/jquery-cookie/1.3.1/jquery.cookie.min.js"></script>
<script...

JavaScript

$('.pagetop a').click(function(){
    $('html body').animate({scrollTop:0},300,'easeInOutQuart');
    return false;
});