JSFiddle - React, Tailwind, and code Playground

HTML

<div id="box"></div>

CSS

#box{
    background:cyan;
    position: absolute;
    height:100px;
    width:100px;
}

JavaScript

function placeBox(event){
    var d = document.getElementById('box');
    d.style.left = event.clientX + 'px';
    d.style.top =  event.clientY + 'px';
}

document.addEventListener("mousemove", placeBox);