diff --git a/vocoder/static/vocoder.js b/vocoder/static/vocoder.js
index b5bc57e..79fd00e 100644
--- a/vocoder/static/vocoder.js
+++ b/vocoder/static/vocoder.js
@@ -1,3 +1,5 @@
+"use strict";
+
 //
 // Vocoder front-end Javascript
 //