webcam-preview.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=
    , initial-scale=1.0">
    <title>Webcam Preview</title>
    <script>
        navigator.mediaDevices.getUserMedia({ video: true }).then((stream) => {
            const video = document.querySelector('#video');
            video.srcObject = stream;
            video.play();
        })
    </script>
    <style>
        body {
            margin: 0;
            padding: 0;
            background: #2f2f2f;
            display: flex;
            align-items: center;
            justify-content: center;
        }

        video {
            width: 80%;
            max-height: 1000px;
        }
    </style>
</head>
<body>
    <video id="video"></video>
</body>
</html>