arg: test(p); // undefined argument var: var d; // undefined variable null: var n = null; []: var a = []; {}: var o = {}; 0: var x = 0; 123: var z = 123; '': var s1 = ''; '0': var s2 = '0'; '123': var s3 = '123'; '1abc': var t = '1abc'; false: var b = false; true: var c = true; NaN: var nan = 1*'x'; Inf: var inf = 1/0;