JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://ajax.microsoft.com/ajax/jquery.validate/1.7/jquery.validate.js"></script>
<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.4/themes/ui-lightness/jquery-ui.css">

<div id='test'>hi</div>

JavaScript

window.onload = function() {

    var myVar;
    myVar = 'test';

    var element = document.getElementById(myVar);
    
    alert(element.innerHTML);
};