JSFiddle - React, Tailwind, and code Playground
HTML
<input type="button" value="Pause" onClick="paused=true" />
<input type="button" value="Resume" onClick="paused=false" />
<div id="time">Time</div>
JavaScript
paused = false;
setInterval(function(){
if (paused) return;
console.log('tick')
var div = document.getElementById('time');
div.innerHTML = (new Date()).toString()
}, 1000)