JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
    <div class="button">Button</div>
    <div class="button">Button</div>
</div>
<div class="button">Button</div>- this last one will not work because it's outside the container
<div id="result">0</div>

CSS

div.button {
    border:1px solid black;
    width:40px;
    padding:10px;
    border-radius:3px;
    cursor:pointer;
}
#result {
    color:red;
}

JavaScript

var click = 0;
window.onload = function () {
    var buttons = document.getElementById('container').querySelectorAll('div.button');
    console.log(buttons);
    for (i = 0; i < buttons.length; i++) {
        buttons[i].onclick = function () {
            click++;
            document.getElementById('result').innerHTML = click;
        }
    }
}