Upload document using Ajax call

 submitHandler: function (form) {
                var $form = $("#frmQuestion"), formData = new FormData(), params = $form.serializeArray();
                $.each(params, function (i, val) {
                    formData.append(val.name, val.value);
                });

                var files = $("input[Type='file']");
                for (var i = 0; i < files.length; i++) {
                    formData.append(files[i].name, $('#' + files[i].id).get(0).files[0]);
                             }

               
                $.ajax({
                    url: '/Questions/SaveQuestion',
                    data: formData,
                    cache: false,
                    contentType: false,
                    processData: false,
                    type: 'POST',
                    mimeType: "multipart/form-data",
                    beforeSend: function () { ShowCustomLoading(true); },
                    complete: function () { ShowCustomLoading(false); },
                    success: function (datas) {

                        var data = JSON.parse(datas)
                        if (data.Key == true) {
                            new PNotify({
                                text: data.Value,
                                delay: 1500,
                                type: 'success'
                            });
                            $("#divlist").show();
                            $("#divAdd").hide();
                            $("#jqTable").trigger('reloadGrid');
                        }
                        else {
                            new PNotify({
                                text: data.Value,
                                delay: 1500,
                                type: 'error'
                            });
                        }
                    }
                });
            }