Untitled

<html>
    <head></head>
    <body>
        <input type="file"/>
        <button>upload</button>
        <p></p>

        <script>
            var input  = document.querySelector('input'),
                button = document.querySelector('button'),
                p      = document.querySelector('p');

            input.addEventListener('change', function(event) {
                var files = event.target.files;
                uploader.addFiles(files);

                p.innerHTML = '';
                for (var i = 0, file; file = uploader.files[i]; i++) {
                    p.innerHTML += 'file: <strong>' + file.name + '</strong> size: <strong>' + file.humanSize + '</strong>';
                }
            });

            button.addEventListener('click', function () {
                uploader.startUpload({
                    url: '/url/to/upload/handler',
                    concurrency: 2,
                    onProgress: function(file) {},
                    onCompleted: function(file, response) {}
                });
            });
        </script>
    </body>
</html>