JSFiddle - React, Tailwind, and code Playground

HTML

<div id="demo"></div>  
<button ux-banana="atributo banana" onclick="myFunction(this)">Clica aqui!</button>

JavaScript

window.myFunction = function (btn) {  
  document.getElementById("demo").innerHTML='Vc clicou no botão com ' + btn.getAttribute('ux-banana');  
};