41   function F() { }  class in TestChains
42   F.prototype = A;  class
43   assertTrue(C instanceof F);
44   assertTrue(B instanceof F);
45   assertFalse(A instanceof F);
47   F.prototype = B;
48   assertTrue(C instanceof F);
49   assertFalse(B instanceof F);
50   assertFalse(A instanceof F);
52   F.prototype = C;
53   assertFalse(C instanceof F);
54   assertFalse(B instanceof F);
55   assertFalse(A instanceof F);
62   function F() { }  class in TestExceptions
67                 F, new F(),