clock.js

const clock = document.getElementById("clock");


function leadZeroFormat(i) {
  if (i<10) {
    i = "0" + i;
  }
  return i;
}

function startClock() {
  const dateObject = new Date();
  let h = dateObject.getHours();
  let m = dateObject.getMinutes();
  let s = dateObject.getSeconds();
  h = leadZeroFormat(h);
  m = leadZeroFormat(m);
  s = leadZeroFormat(s);
  clock.innerHTML = `${h}:${m}:${s}`
  setTimeout(startClock, 500);
}

startClock();