js 图片base64

<!DOCTYPE html>
<html>

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="maximum-scale=1.0,minimum-scale=1.0,user-scalable=0,width=device-width,initial-scale=1.0" />
    <script>
        function init() {
            var canvas = document.createElement('canvas')
            var ctx = canvas.getContext('2d');
            var img = new Image();
            img.src = "临时图片/1.png";
            img.onload = function() {
                //原图的大小
                ctx.drawImage(img, 0, 0, 100, 100);
                console.log(canvas.toDataURL())
                document.getElementById('imgbase64').src = canvas.toDataURL();
            }
        }
    </script>
</head>

<body onload="init()">
    <img id="imgbase64" src="" />
</body>

</html>