JSFiddle - React, Tailwind, and code Playground

by brigand

HTML

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

CSS

#box {
  width: 12em;
  height: 12em;
  animation: 5s slide linear infinite alternate;
  position: relative;
  background: #3399ff;
}

@keyframes slide {
  0% {
    left: 0;
  }
  100% {
    left: calc(100% - 12em);
  }
}

JavaScript

box.addEventListener('mousemove', event => {
  event.currentTarget.textContent = Date.now() % (60 * 1000) / 1000;
})