Fis JS undefined for non logged in users

tasks/guestBookDB/js/textarea.js

@@ -28,7 +28,7 @@ document.addEventListener("DOMContentLoaded", () => {
 
   const addValidation = () => {
     const comment = document.getElementById("comment");
-    comment.addEventListener("input", handlerCounter);
+    comment?.addEventListener("input", handlerCounter);
   };
 
   addValidation();