diff --git a/static/js/rot.js b/static/js/rot.js
index a6d33f31..0c13369e 100644
--- a/static/js/rot.js
+++ b/static/js/rot.js
@@ -77,7 +77,9 @@
         volumeSet(Math.min(1, Math.max(0, audio.volume + number)));
     }
     function updateVolumeLabel() {
-        document.getElementById("user-audio-percentage").innerHTML = Math.round(audio.volume * 100) + "%";
+        let txtElm = document.getElementById("user-audio-percentage");
+        if (txtElm)
+            txtElm.innerHTML = Math.round(audio.volume * 100) + "%";
     }
 
     //Registers a mutation observer for an element. Upon triggering and the callback