JSFiddle - React, Tailwind, and code Playground
HTML
<output></output>
CSS
output {
display:block;
height:10em;
overflow:auto;
border:2px inset #ccc;
resize:y;
}
JavaScript
var output = document.querySelector('output');
var then = new Date();
setInterval(function(){
var now = new Date();
output.innerHTML += now - then + 'ms<br>';
output.scrollTop = output.scrollHeight - output.clientHeight;
then = now;
}, 1000);