diff --git a/web/game.html b/web/game.html
index a3435c7a..b38f222f 100644
--- a/web/game.html
+++ b/web/game.html
@@ -31,7 +31,7 @@
         </div>
 
         <div id="bottom-screen">
-            <!--NOTE: New browser doesn't allow unmuted video player. So we muted here. 
+            <!--NOTE: New browser doesn't allow unmuted video player. So we muted here.
                 There is still audio because current audio flow is not from media but it is manually encoded (technical webRTC challenge). Later, when we can integrate audio to media, we can face the issue with mute again .
                 https://developers.google.com/web/updates/2017/09/autoplay-policy-changes
             -->
@@ -90,7 +90,7 @@
 
     <script src="/static/js/log.js?v=3"></script>
     <script src="/static/js/env.js?v=3"></script>
-    <script src="/static/js/event/event.js?v=3"></script>
+    <script src="/static/js/event/event.js?v=4"></script>
     <script src="/static/js/input/keys.js?v=3"></script>
     <script src="/static/js/input/input.js?v=3"></script>
     <script src="/static/js/gameList.js?v=3"></script>
diff --git a/web/js/event/event.js b/web/js/event/event.js
index 58372e11..6dd29eaf 100644
--- a/web/js/event/event.js
+++ b/web/js/event/event.js
@@ -48,7 +48,7 @@ const event = (() => {
             if (!topics[topic] || topics[topic].length < 1) return;
 
             topics[topic].forEach((listener) => {
-                listener.listener(data || {})
+                listener.listener(data !== undefined ? data : {})
             });
         }
     }