js中根据身份证号自动填充生日信息

//证件类型与证件号
var card_type = '......';
var card_no = '......';
//生日
var birthday = '';

if (card_type === '身份证') {
  if (card_no != null && card_no != "") {
    if (card_no.length === 15) {
      birthday = "19" + card_no.substr(6, 6);
    } else if (card_no.length === 18) {
      birthday = card_no.substr(6, 8);
    }
  }
}

birthday = birthday.replace(/(.{4})(.{2})/,"$1-$2-");