diff --git a/mithril.js b/mithril.js
index c3380cc2..5734c837 100644
--- a/mithril.js
+++ b/mithril.js
@@ -1,4 +1,4 @@
-Mithril = m = new function app(window) {
+Mithril = m = new function app(window, undefined) {
 	var type = {}.toString
 	var parser = /(?:(^|#|\.)([^#\.\[\]]+))|(\[.+?\])/g, attrParser = /\[(.+?)(?:=("|'|)(.*?)\2)?\]/