Demo

Full Screen

Video

YouTube Channel

Code

HTML

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width,initial-scale=1">
    <title>Digital Clock with HTML, CSS & JavaScript</title>
    <link rel="stylesheet" type="text/css" href="style.css">
  </head>
  <body>
    <div class="clock">
      <div class="clock-date">Sunday, January 01, 2022</div>
      <div class="clock-time">00:00:00</div>
    </div>
    <script src="clock.js"></script>
  </body>
</html>

CSS

@charset "utf-8";
@import url('https://fonts.googleapis.com/css2?family=Roboto:wght@700&display=swap');
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
html {
  font-size: 16px;
}
body {
  display: flex;
  justify-content: center;
  align-items: center;
  width: 100%;
  height: 100vh;
  background-color: #000;
  font-family: 'Roboto', sans-serif;
}
.clock {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  position: relative;
  z-index: 10;
  padding: 30px 30px 20px;
  border-radius: 10px;
  background-color: #3551ff;
  color: #fff;
  letter-spacing: 1px;
}
.clock::before {
  position: absolute;
  top: -2px;
  right: -2px;
  bottom: -2px;
  left: -2px;
  z-index: -1;
  filter: blur(10px);
  border-radius: 10px;
  background-color: #3551ff;
  content: '';
}
.clock-date {
  font-size: 1.25rem;
}
.clock-time {
  font-size: 5rem;
}
@media screen and (max-width: 480px) {
  .clock {
    padding: 20px 20px 10px;
  }
  .clock-date {
    font-size: .9375rem;
  }
  .clock-time {
    font-size: 3.75rem;
  }
}

JavaScript

function clock() {
  let d = new Date();

  let year = d.getFullYear();
  let month = d.toLocaleString("en-US", {
    month: "long",
  });
  let date = ("0" + d.getDate()).slice(-2);
  let dayNum = d.getDay();
  let day = ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"][dayNum];
  let hr = ("0" + d.getHours()).slice(-2);
  let min = ("0" + d.getMinutes()).slice(-2);
  let sec = ("0" + d.getSeconds()).slice(-2);

  document.querySelector(".clock-date").innerHTML = day + ", " + month + " " + date + ", " + year;
  document.querySelector(".clock-time").innerHTML = hr + ":" + min + ":" + sec;
}

setInterval(clock, 1000);