HTML5 D&Dによるファイルアップロード

(function ($) {
    $.fn.upload = function(options) {
        var defer = $.Deferred();
        var settings = {
            url: null,
            urlBase: null
        };
        if (options) {
            $.extend(settings, options);
        }

        var $this = $(this);

        $this.on('dragenter dragover', function() {
            return false;
        });
        $this.on('drop', function(e) {
            e.preventDefault();

            var file = e.originalEvent.dataTransfer.files[0];
            var reader = new FileReader();

            reader.onload = function(e) {
                var xhr = new XMLHttpRequest();
                var url = settings.url;

                xhr.open('POST', url, true);

                var filetype = file.type;

                if (_.isEmpty(filetype)) {
                    filetype = 'application/octet-stream';
                }

                xhr.setRequestHeader('Content-Type', filetype);

                xhr.onload = function(e) {
                    if (this.status === 200) {
                        return defer.resolve();
                    } else {
                        return defer.reject();
                    }
                };

                xhr.send(file);
            };

            reader.readAsBinaryString(file);
        });

        return defer.promise();
    };
})(jQuery);