diff --git a/core/misc/announce.js b/core/misc/announce.js
index ed02038..3037436 100644
--- a/core/misc/announce.js
+++ b/core/misc/announce.js
@@ -16,6 +16,8 @@
  */
 (function (Drupal, debounce) {
 
+  "use strict";
+
   var liveElement;
   var announcements = [];