diff --git a/lib/class.js b/lib/class.js
index fbfd750..72e2968 100644
--- a/lib/class.js
+++ b/lib/class.js
@@ -65,7 +65,7 @@ function Class() {};
  */
 var extend = ( function( extending )
 {
-    extending = false;
+    var extending = false;
 
     /**
      * Mimics class inheritance