<div id='seconds-counter'></div>
body {
  background: black;
  color: white;
  font-size: 2rem;
  color: Yellow
}
let seconds = 0;
let el = document.getElementById( 'seconds-counter' );

function incrementSeconds() {
    seconds += 1;
    el.innerText = "Loaded " + seconds + " seconds ago.";
}

let cancel = setInterval( incrementSeconds, 1000 );

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.