jQueryAjaxUpload.js

(function ($) {

    var defaults = {
        cache: false,
        contentType: false,
        processData: false,
        type: 'POST',
        onProgress: new Function,
        xhr: function (xhr) {

            var xhr = $.ajaxSettings.xhr();

            xhr.upload.addEventListener('progress', function(e) {
                var percent = parseFloat(((e.loaded / e.total) * 100).toFixed(2));

                defaults.onProgress(percent, e);

            }, false);

            return xhr;
        },

    };

    $.fn.ajaxUpload = function (options) {

        var formData = new FormData;

        // if element is a form, find all inputs 

        if (this.is('form')) {

            var $el = this.find(':input');

        } else {

            var $el = this;
        }

        $el.each(function() {

            var $that = $(this);

            var name = $that.attr('name');

            var files = $that.prop('files');

            var value = $that.val();

            if (!name) return;

            // when input not has file, we know that is a common input

            if (!files) {

                formData.append(name, value);

            } else {

                // Handles single file or multiple file

                $.each(files, function(i, file) {
                    formData.append(name, file)
                });
            }
        })

        options = $.extend({}, defaults, options, {
            data: formData
        });

        $.ajax(options);
    }

})( jQuery );

O uso disso é

$('.change').change(function () {
     $('form.form-upload').ajaxUpload({url: 'testando'});
});