JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" placeholder="escreve algo aqui...">
<div id="res"></div>

JavaScript

var input = document.querySelector('input');
var res = document.getElementById('res');
input.addEventListener('keyup', function() {
    var valido = this.value.match(/^[\d\w]+$/);
    res.innerHTML = valido ? 'valido' : 'invalido';
});