JSFiddle - React, Tailwind, and code Playground
HTML
<input type="text" id="myInput" />
<div id="myOutput"></div>
JavaScript
var myInput = document.getElementById('myInput');
var myOutput = document.getElementById('myOutput');
var myEvent = "onkeyup";
myInput[myEvent] = function(){
myOutput.innerHTML = myInput.value;
};