<!doctype html>
<html>

<head>
    <title>Canvas HTML5</title>
    <style>
        #canvas {
            border: 1px solid black;
        }
    </style>
</head>

<body>
    <div><label>Image</label>
        <input type="file" id="imgLoader" name="imgLoader">
    </div>
    <div><canvas id="canvas"></canvas></div>
    <script>
        const canvas = document.querySelector('#canvas');
        const ctx = canvas.getContext('2d');
        const imgLoader = document.querySelector('#imgLoader');
        imgLoader.addEventListener('change', handleUpload);

        function handleUpload(e) {
            console.log(e);
            const reader = new FileReader();
            reader.onload = function (e) {
                console.log(e);
                const img = new Image();
                img.onload = function () {
                    canvas.width = img.width / 2;
                    canvas.height = img.height / 2;
                    ctx.drawImage(img, 0, 0, img.width / 2, img.height / 2);
                }
                img.src = e.target.result;
            }
            reader.readAsDataURL(e.target.files[0]);
        }

    </script>
</body>

</html>
