diff --git a/index.js b/index.js
index ea2e368..9bb28c7 100644
--- a/index.js
+++ b/index.js
@@ -10,8 +10,8 @@
 
 	var canUseDOM = !!(
 		typeof window !== 'undefined' &&
-		window.document &&
-		window.document.createElement
+		typeof window.document !== 'undefined' &&
+		typeof window.document.createElement !== 'undefined'
 	);
 
 	var ExecutionEnvironment = {