diff --git a/src/js/plyr.js b/src/js/plyr.js
index 6bf77be3..280d5f19 100644
--- a/src/js/plyr.js
+++ b/src/js/plyr.js
@@ -2680,7 +2680,7 @@
 }));
 
 // Custom event polyfill
-//
+// https://developer.mozilla.org/en-US/docs/Web/API/CustomEvent/CustomEvent
 (function () {
     function CustomEvent (event, params) {
         params = params || { bubbles: false, cancelable: false, detail: undefined };