JS 识别生日、性别、年龄

<script>
function IdCard(UUserCard,num){
if(num==1){
//获取出生日期
birth=UUserCard.substring(6, 10) + "-" + UUserCard.substring(10, 12) + "-" + UUserCard.substring(12, 14);
return birth;
}
if(num==2){
//获取性别
if (parseInt(UUserCard.substr(16, 1)) % 2 == 1) {
//男
return "男";
} else {
//女
return "女";
}
}
if(num==3){
//获取年龄
var myDate = new Date();
var month = myDate.getMonth() + 1;
var day = myDate.getDate();
var age = myDate.getFullYear() - UUserCard.substring(6, 10) - 1;
if (UUserCard.substring(10, 12) < month || UUserCard.substring(10, 12) == month && UUserCard.substring(12, 14) <= day) {
age++;
}
return age;
}
}
alert (IdCard('440981199105221234',3));
    alert (IdCard('440981199105221234',2));
    alert (IdCard('440981199105221234',1));
</script>