function getAge(y,m,d) {

    var today = new Date();

    m = m - 1;

    var birthDate = new Date(y, m, d);

    console.log('birthDate: ' + birthDate);

    var age = today.getFullYear() - birthDate.getFullYear();

    var m = today.getMonth() - birthDate.getMonth();

    if (m < 0 || (m === 0 && today.getDate() < birthDate.getDate())) {

        age--;

    }

    return age;

}

​

​

console.log('age: ' + getAge(1980, 08, 10));