script.js

const body = document.querySelector("body")
const hourEl = document.getElementById("hour")
const minuteEl = document.getElementById("minutes")
const secondEl = document.getElementById("seconds")
const ampmEl = document.getElementById("ampm")

function updateClock() {
  let h = new Date().getHours()
  let m = new Date().getMinutes()
  let s = new Date().getSeconds()
  let ampm = "AM"

  if (h > 12) {
    h = h - 12
    ampm = "PM"
    ampmEl.style.background = "red"
    body.style.backgroundImage = "url('./img-night.jpg')"
  }

  h = h < 10 ? "0" + h : h
  m = m < 10 ? "0" + m : m
  s = s < 10 ? "0" + s : s

  hourEl.innerText = h
  minuteEl.innerText = m
  secondEl.innerText = s
  ampmEl.innerText = ampm
  setTimeout(() => {
    updateClock()
  }, 1000);
}

updateClock()