michael@0: var s = '';
michael@0: 
michael@0: var a = [, 0, 1];
michael@0: for (var i in a) {
michael@0:     a.reverse();
michael@0:     s += i + ',';
michael@0: }
michael@0: 
michael@0: // Index of the element with value '0'.
michael@0: assertEq(s, '1,');
michael@0: