常用正则表达式

                if (!IdCard.test(num)) {alert("输入的身份证号不正确！"); return false;}

                            var len = num.length, re;

                            if (len == 15)

                            re = new RegExp(/^(\d{6})()?(\d{2})(\d{2})(\d{2})(\d{3})$/);

                            else if (len == 18)