The Tor Browser / file revision

 function A() {};

 A.prototype = [];

 function B() {};

 B.prototype = new A();

 function C() {};

 C.prototype = new B();

 function D() {};

 D.prototype = new C();

 function E() {};

 E.prototype = new D();

 function f() {

     var o = new B();

     for (var i=0; i<10; i++)

 	o[i] = i;

     var expected = '{"0":0,"1":1,"2":2,"3":3,"4":4,"5":5,"6":6,"7":7,"8":8,"9":9}';

     assertEq(JSON.stringify(o), expected);

     var o = new A();

     for (var i=0; i<10; i++)

 	o[i] = i;

     assertEq(JSON.stringify(o), expected);

     var o = new D();

     for (var i=0; i<10; i++)

 	o[i] = i;

     assertEq(JSON.stringify(o), expected);

     var o = new E();

     for (var i=0; i<10; i++)

 	o[i] = i;

     assertEq(JSON.stringify(o), expected);

 }

 f();