diff --git a/dango.js b/dango.js
index 9725ab3..6075e05 100644
--- a/dango.js
+++ b/dango.js
@@ -1,3 +1,5 @@
+'use strict'
+
 // function require (file) {
 //  return window[file.replace(/^\.[\/\\]/,'').replace(/.js$/,'')];
 // }