JSFiddle - React, Tailwind, and code Playground

HTML

<h1>Put this page in a background tab on Safari</h1>
<div id="output" />

JavaScript

var interval = 2000;
var scriptTime = new Date().getTime();
function addTime(){
	scriptTime += interval;
  	document.getElementById('output').innerHTML = "Current state: scripts delayed by "+(new Date().getTime()-scriptTime)+"ms";
}
setInterval(addTime, interval);