diff --git a/js-types-n-oop.js b/js-types-n-oop.js
index 128d950..113ae86 100755
--- a/js-types-n-oop.js
+++ b/js-types-n-oop.js
@@ -131,6 +131,12 @@
 	typeof('meaning of life') // -> 'string'
 
 
+// Note that this has a small "inconsistency" that can be used to check 
+// if a variable is defined.
+
+	typeof(unknown_variable) // -> 'undefined'
+
+
 
 // Objects
 // -------