js点击下载图片

代码展示
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>图片保存</title>
</head>
<body>
    <img src="test.jpg" id="Download">
</body>
<script>
    var Download = document.getElementById("Download");
    // 保存文件函数
    Download.onclick = function(){
        var data = this.src;
        console.log(data); 
        var filename='ercode';
        var save_link = document.createElementNS('http://www.w3.org/1999/xhtml', 'a');
        save_link.href = data;
        save_link.download = filename;
       
        var event = document.createEvent('MouseEvents');
        event.initMouseEvent('click', true, false, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null);
        save_link.dispatchEvent(event);
    }
</script>
</html>