JSFiddle - React, Tailwind, and code Playground

HTML

<p>Cliques no botão: <span id="clickCounter">0</span></p>
<button id="button">Clique aqui!</button>
<p>Eventos keypress: <span id="keyCounter">0</span></p>

JavaScript

(function () {
    var clickCounter, keyCounter, btn, val;
    clickCounter = document.getElementById('clickCounter');
    keyCounter   = document.getElementById('keyCounter');
    btn          = document.getElementById('button');
    function increment(element) {
        var val = element.firstChild.nodeValue;
        element.firstChild.nodeValue = parseInt(val, 10) + 1;
    }
    btn.onclick  = function (event) {
        event = event || window.event;
        return event instanceof Event && event.detail && increment(clickCounter);
    };
    window.onkeypress = function () {
        increment(keyCounter);
    };
}());

//


/*var e = {};
e = new Event('click');
e.detail = 1;

console.log( e instanceof Event, e.detail );

document.getElementById( 'button' ).onclick(e);
*/