JSFiddle - React, Tailwind, and code Playground

HTML

<div id="a" src="test"></div>

JavaScript

window.onload = function() {
    var a = document.getElementById("a"),
        x = a.getAttribute("src");
    a.setAttribute("data", x);
    a.removeAttribute("src");
    
    alert(document.getElementsByTagName("body")[0].innerHTML);
}