JSFiddle - React, Tailwind, and code Playground

HTML

<div id="display">0</div>
<input type="text" id="cpf_cnpj">

JavaScript

var count = 0;
var display = document.getElementById('display')

function myFunction() { display.textContent = (++count).toString(); }

document.addEventListener('DOMContentLoaded', myFunction);
document.getElementById('cpf_cnpj').addEventListener('change', myFunction);