JSFiddle - React, Tailwind, and code Playground

HTML

<div id="mouse"></div>

CSS

#mouse {
  position: fixed;
  width: 100px;
  height: 100px;
  outline: 1px solid red;
}

JavaScript

const mouse = document.getElementById('mouse');
window.addEventListener("mousemove", e => {
  mouse.style.left = e.offsetX + 'px';
  mouse.style.top = e.offsetY + 'px';
  console.log(e.offsetX, e.offsetY);
});