diff --git a/css/player-base.js b/css/player-base.js
index 505f12f9..ca006b19 100644
--- a/css/player-base.js
+++ b/css/player-base.js
@@ -25,6 +25,7 @@ document.addEventListener("DOMContentLoaded", () => {
     // raw media elements
     const videoEl = document.getElementById('video');
     const audio = document.getElementById('aud');
+    const audioEl = document.getElementById('aud');
 
     // resolve initial sources robustly (works whether <audio src> or <source> children are used)
     const pickAudioSrc = () => {