Building a Screen Recorder using HTML, CSS, and JS: A Step-by-Step Guide

3 min readAug 15, 2023

Introduction:

Screen recording has become an essential tool for various purposes, from creating tutorials to sharing gameplay highlights. In this tutorial, we’ll walk you through the process of building a screen recorder using HTML, CSS, and JavaScript. By the end of this guide, you’ll have a functional screen recorder that captures your screen activity and saves it as a video file. Let’s dive in!

Prerequisites:

Basic understanding of HTML, CSS, and JavaScript
Code editor of your choice

1. Setting Up the HTML Structure:

Start by creating the basic HTML structure for the screen recorder interface. Use HTML5’s video element to display the recorded content.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Screen Recorder</title>
    <link rel="stylesheet" href="styles.css">
</head>
<body>
    <div class="container">
        <video id="recordedVideo" controls></video>
        <button id="startBtn">Start Recording</button>
        <button id="stopBtn">Stop Recording</button>
    </div>
    <script src="script.js"></script>
</body>
</html>

2. Styling the User Interface:

Style your screen recorder interface using CSS to make it visually appealing and user-friendly.

body {
    font-family: Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    background-color: #f5f5f5;
}

.container {
    text-align: center;
    background-color: white;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0px 0px 10px rgba(0, 0, 0, 0.2);
}

button {
    padding: 10px 20px;
    margin: 10px;
    border: none;
    border-radius: 5px;
    background-color: #007bff;
    color: white;
    cursor: pointer;
}

3. Capturing Screen Using Web APIs:

Use the getDisplayMedia API to capture the screen or a specific application window.

const startBtn = document.getElementById('startBtn');
const stopBtn = document.getElementById('stopBtn');
const recordedVideo = document.getElementById('recordedVideo');
let mediaRecorder;
let recordedChunks = [];

startBtn.addEventListener('click', async () => {
    const stream = await navigator.mediaDevices.getDisplayMedia({ video: true });
    mediaRecorder = new MediaRecorder(stream);

    mediaRecorder.ondataavailable = event => {
        if (event.data.size > 0) {
            recordedChunks.push(event.data);
        }
    };

    mediaRecorder.start();
});

stopBtn.addEventListener('click', () => {
    mediaRecorder.stop();
});

4. Recording Screen Activity:

Handle the recording process using the MediaRecorder API and store the recorded data.

5. Saving the Recorded Video:

Combine the recorded chunks into a Blob and create a URL to display the recorded video.

mediaRecorder.onstop = () => {
    const blob = new Blob(recordedChunks, { type: 'video/webm' });
    recordedVideo.src = URL.createObjectURL(blob);
    recordedChunks = [];
};

6. Conclusion:

Congratulations! You’ve successfully built a screen recorder using HTML, CSS, and JavaScript. Users can now capture their screen activity, record videos, and save them for later use. This simple implementation can be further enhanced with features like customizing recording options, adding pause/resume functionality, and implementing a more polished user interface.

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