diff --git a/Definitions/jqueryui-1.9.d.ts b/Definitions/jqueryui-1.9.d.ts
index d55d03a1a..1cf4cc775 100644
--- a/Definitions/jqueryui-1.9.d.ts
+++ b/Definitions/jqueryui-1.9.d.ts
@@ -144,7 +144,20 @@ interface DatepickerOptions {
     yearSuffix?: string;
 }
 
+interface DatepickerFormatDateOptions {
+    dayNamesShort?: string[];
+    dayNames?: string[];
+    monthNamesShort?: string[];
+    monthNames?: string[];
+}
+
 interface Datepicker extends Widget, DatepickerOptions {
+    regional: { [languageCod3: string]: any; };
+    setDefaults(defaults: DatepickerOptions);
+    formatDate(format: string, date: Date, settings?: DatepickerFormatDateOptions): void;
+    parseDate(format: string, date: Date, settings?: DatepickerFormatDateOptions): void;
+    iso8601Week(date: Date): void;
+    noWeekends(): void;
 }
 
 
@@ -287,31 +300,6 @@ interface DroppableEvents {
 interface Droppable extends Widget, DroppableOptions, DroppableEvents {
 }
 
-// TODO ?
-interface JQueryDatePickerDefaults {
-    closeText: string;
-    prevText: string;
-    nextText: string;
-    currentText: string;
-    monthNames: string[];
-    monthNamesShort: string[];
-    dayNames: string[];
-    dayNamesShort: string[];
-    dayNamesMin: string[];
-    weekHeader: string;
-    dateFormat: string;
-    firstDay: number;
-    isRTL: bool;
-    showMonthAfterYear: bool;
-    yearSuffix: string;
-}
-
-interface JQueryDatePicker {
-    regional: any;
-    setDefaults(JQueryDatePickerDefaults);
-}
-
-
 // Menu //////////////////////////////////////////////////
 
 interface MenuOptions {
@@ -931,7 +919,7 @@ interface JQuery {
 
 interface JQueryStatic {
     ui: UI;
-    datepicker: JQueryDatePicker;
+    datepicker: Datepicker;
     widget: Widget;
     Widget: Widget;
 }
\ No newline at end of file
diff --git a/Tests/jqueryui-tests.ts b/Tests/jqueryui-tests.ts
index fba9d5932..21e48f759 100644
--- a/Tests/jqueryui-tests.ts
+++ b/Tests/jqueryui-tests.ts
@@ -44,7 +44,15 @@ function test_draggable() {
         helper: (event) => { return $("<div class='ui-widget-header'>I'm a custom helper</div>"); }
     });
     $("#set div").draggable({ stack: "#set div" });
-
+    $.datepicker.formatDate('yy-mm-dd', new Date(2007, 1 - 1, 26));
+    $.datepicker.formatDate('DD, MM d, yy', new Date(2007, 7 - 1, 14), {
+        dayNamesShort: $.datepicker.regional['fr'].dayNamesShort, 
+        dayNames: $.datepicker.regional['fr'].dayNames, 
+        monthNamesShort: $.datepicker.regional['fr'].monthNamesShort, 
+        monthNames: $.datepicker.regional['fr'].monthNames
+    });
+    $("#datepicker").datepicker({ beforeShowDay: $.datepicker.noWeekends });
+    $("selector").datepicker($.datepicker.regional['fr']);
 }
 
 function test_droppable() {
@@ -1128,6 +1136,9 @@ function test_datepicker() {
     $(".selector").datepicker({ dateFormat: "yy-mm-dd" });
     $(".selector").datepicker({ dayNames: ["Dimanche", "Lundi", "Mardi", "Mercredi", "Jeudi", "Vendredi", "Samedi"] });
     $(".selector").datepicker({ dayNamesMin: ["Di", "Lu", "Ma", "Me", "Je", "Ve", "Sa"] });
+
+    $.datepicker.setDefaults($.datepicker.regional[""]);
+    $(selector).datepicker($.datepicker.regional["fr"]);
 }