diff -r 000000000000 -r 6474c204b198 js/src/tests/js1_5/Regress/regress-240577.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/js1_5/Regress/regress-240577.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,37 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/*
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/licenses/publicdomain/
+ * Contributor: Bob Clary
+ */
+
+//-----------------------------------------------------------------------------
+// originally reported by Jens Thiele <karme@unforgettable.com> in
+var BUGNUMBER = 240577;
+var summary = 'object.watch execution context';
+var actual = '';
+var expect = '';
+
+printBugNumber(BUGNUMBER);
+printStatus (summary);
+
+var createWatcher = function ( watchlabel )
+{
+  var watcher = function (property, oldvalue, newvalue)
+  {
+    actual += watchlabel; return newvalue;
+  };
+  return watcher;
+};
+
+var watcher1 = createWatcher('watcher1');
+
+var object = {property: 'value'};
+
+object.watch('property', watcher1);
+
+object.property = 'newvalue';
+
+expect = 'watcher1';
+
+reportCompare(expect, actual, summary);