131− hex = hex + ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b',
131+ hex = hex + ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B',
132− 'c', 'd', 'e', 'f'][Math.floor(Math.random() * 16)]
132+ 'C', 'D', 'E', 'F'][Math.floor(Math.random() * 16)]