JSFiddle - React, Tailwind, and code Playground

HTML

<input type="checkbox" id="cb" />
<button id="btn">Change Checkbox</button>
<div id="msg"></div>

JavaScript

var count = 0;
var cb = document.getElementById("cb");
var btn = document.getElementById("btn");
var msg = document.getElementById("msg");
cb.addEventListener("change", cb_onChange);
btn.addEventListener("click", btn_onClick);

function btn_onClick() {
    cb.checked = !cb.checked;
}

function cb_onChange() {
    msg.innerHTML = "Checkbox changed " + count+++" times";
}