JSFiddle - React, Tailwind, and code Playground
HTML
<input id='input'>
<div id='output'></div>
JavaScript
var input = document.getElementById("input").oninput = inputChange;
function inputChange() {
if ( event.target.value.length )
document.getElementById("output").innerText = "input have text"
else
document.getElementById("output").innerText = "input not have text"
}