JSFiddle - React, Tailwind, and code Playground

HTML

<div id="keyCode1">&nbsp;</div>
<div id="keyCode2"></div>

JavaScript

window.addEventListener( "keypress", doKeyPress, false );
window.addEventListener( "keydown", doKeyDown, false );

var _keyDiv1 = document.getElementById('keyCode1');
var _keyDiv2 = document.getElementById('keyCode2');

function doKeyPress(e) {
    _keyDiv1.innerHTML = e.keyCode;
}

function doKeyDown(e) {
    _keyDiv2.innerHTML = e.keyCode;
}