function foo(d){ return Date.prototype.getTimezoneOffset.call(d); } noInline(foo); var x; var count = 100000; for (var i = 0 ; i < count; i++){ try { foo(i < count - 1000 ? new Date() : "a"); x = false; } catch (e) { x = true; } } if (!x) throw "bad result: "+ x;