JSFiddle - React, Tailwind, and code Playground

HTML

<img id="keys" src="http://i.stack.imgur.com/gTiMi.png">
<div>
Spot is: <span id="spot"></span>
</div>

JavaScript

var keys = document.getElementById("keys");
var keysTop = keys.offsetTop;
var keysLeft = keys.offsetLeft;
var spot = document.getElementById("spot");
document.getElementById("keys").onclick = function (event) {
   spot.innerHTML = "(" + (event.clientX - keysLeft) + " , " + (event.clientY - keysTop) + ")";
}