i18n

cms/templates/textbooks.html

@@ -38,7 +38,7 @@ $(function() {
     $(window).on("beforeunload", function() {
         var dirty = textbooks.find(function(textbook) { return textbook.isDirty(); });
         if(dirty) {
-            return "You have unsaved changes. Do you really want to leave this page?";
+            return gettext("You have unsaved changes. Do you really want to leave this page?");
         }
     })
 })