diff --git a/web/skins/classic/js/skin.js b/web/skins/classic/js/skin.js
index 2610d89fa..b5a066e5f 100644
--- a/web/skins/classic/js/skin.js
+++ b/web/skins/classic/js/skin.js
@@ -913,7 +913,3 @@ function initThumbAnimation() {
     });
   }
 }
-
-function sleep(ms) {
-  return new Promise(resolve => setTimeout(resolve, ms));
-}