diff --git a/classy.js b/classy.js
index 9ca6051..10402c9 100644
--- a/classy.js
+++ b/classy.js
@@ -4,14 +4,15 @@
  * :copyright: (c) 2011 by Armin Ronacher. 
  * :license: BSD.
  */
+!function (context) {
+'use strict';
 !function (definition) {
   if (typeof module != 'undefined' && module.exports) module.exports = definition()
   else if (typeof define == 'function' && typeof define.amd == 'object') define(definition)
-  else this.Class = definition()
-}(function (undefined) {
+  else context.Class = definition()
+}(function (undefined) { 
   var
     CLASSY_VERSION = '1.4',
-    context = this,
     old = context.Class,
     disable_constructor = false;
 
@@ -122,7 +123,7 @@
     var rv = function() {
       if (disable_constructor)
         return;
-      var proper_this = context === this ? cheapNew(arguments.callee) : this;
+      var proper_this = this instanceof rv ? this : cheapNew(rv);
       if (proper_this.__init__)
         proper_this.__init__.apply(proper_this, arguments);
       proper_this.$class = rv;
@@ -158,4 +159,5 @@
 
   /* export the class */
   return Class;
-});
\ No newline at end of file
+});
+}(this);