Fix selecting elements with invalid summaryListSelector

See #2508

diff --git a/wcfsetup/install/files/js/WoltLabSuite/Core/Ui/Reaction/CountButtons.js b/wcfsetup/install/files/js/WoltLabSuite/Core/Ui/Reaction/CountButtons.js
index 4bb40fb170150487fc4ea49b9f95d18800268301..18d60674e9e268ac854b3e53e213ebad91f89ae6 100644 (file)
--- a/wcfsetup/install/files/js/WoltLabSuite/Core/Ui/Reaction/CountButtons.js
+++ b/wcfsetup/install/files/js/WoltLabSuite/Core/Ui/Reaction/CountButtons.js
@@ -168,9 +168,11 @@ define(
                        _initReactionCountButtons: function(element, elementData) {
                                var summaryList = elBySel(this._options.summaryListSelector, element);
                                
-                               var elements = elBySelAll('li', summaryList);
-                               for (var i = 0, length = elements.length; i < length; i++) {
-                                       this._initReactionCountButton(elements[i], elementData.objectId);
+                               if (summaryList !== null) {
+                                       var elements = elBySelAll('li', summaryList);
+                                       for (var i = 0, length = elements.length; i < length; i++) {
+                                               this._initReactionCountButton(elements[i], elementData.objectId);
+                                       }
                                }
                        },