jquery 身份证号码获取年龄验证未成年人

// 验证未成年人
    function isUnderage(idCard) {
        //获取年龄
        var ageDate = new Date()
        var month = ageDate.getMonth() + 1
        var day = ageDate.getDate()
        var age = ageDate.getFullYear() - idCard.substring(6, 10) - 1
        if (idCard.substring(10, 12) < month || idCard.substring(10, 12) === month && idCard.substring(12, 14) <= day) {
            age++
        }
        if (age <= 0) {
            age = 1
        }
        console.log(age);
        if(age<18){
            return false;
        }else{
            return true;
        }
    }