JS gets birthday, age, gender through ID number

<script>
function IdCard(UUserCard,num){
   if(num==1){
       // get the date of birth
       birth=UUserCard.substring(6, 10) + "-" + UUserCard.substring(10, 12) + "-" + UUserCard.substring(12, 14);
    return birth;
   }
   if(num==2){
       //get gender
       if (parseInt(UUserCard.substr(16, 1)) % 2 == 1) {
           //male
     return "男";
       } else {
           //Female
     return "女";
       }
   }
   if(num==3){
        //get age
        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('142223198503226111',3));
</script>