You can create an app for counting numbers using JavaScript to help users count items or products or something.

And this article is creating a Counter app using HTML, CSS, and JavaScript. And source code, you can get from (Tilak Jain): GitHub

HTML/CSS/JavaScript Contents:

1. Create an HTML file (index.html)

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Counter App</title>
    <link rel="stylesheet" href="./style.css">
</head>

<body>
    <h1>Counter App</h1>

    <p class="counter-preview">0</p>
    <div class="buttons" id="allBtns">
        <button class="decrement" id="decrement">
            Decrement
        </button>
        <button class="reset" id="reset">Reset</button>
        <button class="increment" id="increment">Increment</button>
    </div>

    <script src="./script.js"></script>
</body>

</html>

2. Create CSS StyleSheet (style.css)

*{
    box-sizing: border-box;
    margin: 0;
}

body {
    font-family: 'Open Sans', sans-serif;
    font-size: 16px;
    color: #333;
    width: 400px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 90vh;
    background: #A8DCF0;
}

h1 {
    text-transform: uppercase;
}

.counter-preview {
    font-size: 8rem;
    font-weight: bold;
    color: #333;
}

button {
    color: #fff;
    border: none;
    padding: 10px 20px;
    border-radius: 5px;
    font-size: 18px;
    cursor: pointer;
    margin-top: 20px;
    margin-left: 1rem;
}

.decrement {
    background-color: #4caf50;
}

.reset {
    background-color: #f44336;
}

.increment {
    background-color: #2196f3;
}

A result of HTML & CSS, after your coding

3. Create JavaScript (script.js)

const display = document.querySelector('.counter-preview');
const allBtns = document.querySelector('#allBtns');

allBtns.addEventListener('click', counter);

let value = 0;
function counter(e) {
  const btn = e.target.id;
  if (btn === 'increment') {
    value += 1;
  } else if (btn === 'decrement') {
    value -= 1;
  } else {
    value = 0;
  }

  display.textContent = value;
}

Final Result:

JavaScript – Digital Clock with Date

A digital clock is a type of clock that displays the time digitally (i.e. in numerals or other symbols), as opposed to an analog clock.

And this article is creating a Digital Clock using HTML, CSS, and JavaScript.

JavaScript – How to create Stopwatch

A Stopwatch is a timepiece designed to measure the amount of time that elapses between its activation and deactivation. A mechanical stopwatch.

And this article is creating a Stopwatch using HTML, CSS, and JavaScript.