2 files changed, 8 insertions, 0 deletions
diff --git a/django/contrib/admin/static/admin/js/calendar.js b/django/contrib/admin/static/admin/js/calendar.js
index 8432ebd1bf..57655602ee 100644
--- a/django/contrib/admin/static/admin/js/calendar.js
+++ b/django/contrib/admin/static/admin/js/calendar.js
@@ -204,4 +204,5 @@ depends on core.js for utility functions like removeChildren or quickElement
         }
     };
     window.Calendar = Calendar;
+    window.CalendarNamespace = CalendarNamespace;
 })();
diff --git a/django/contrib/admin/static/admin/js/core.js b/django/contrib/admin/static/admin/js/core.js
index a5164ccd47..edccdc0217 100644
--- a/django/contrib/admin/static/admin/js/core.js
+++ b/django/contrib/admin/static/admin/js/core.js
@@ -153,8 +153,15 @@ function findPosY(obj) {
         return this.getTwoDigitHour() + ':' + this.getTwoDigitMinute() + ':' + this.getTwoDigitSecond();
     };
 
+    Date.prototype.getFullMonthName = function() {
+        return typeof window.CalendarNamespace === "undefined"
+            ? this.getTwoDigitMonth()
+            : window.CalendarNamespace.monthsOfYear[this.getMonth()];
+    };
+
     Date.prototype.strftime = function(format) {
         var fields = {
+            B: this.getFullMonthName(),
             c: this.toString(),
             d: this.getTwoDigitDate(),
             H: this.getTwoDigitHour(),