text: function setBirthDate() {
    document.querySelector('#age').innerHTML = _calculateAge(new Date('10-25-1995'));
  }
  
  function _calculateAge(birthday) { // birthday is a date
    const ageDifMs = Date.now() - birthday.getTime();
    const ageDate = new Date(ageDifMs); // milliseconds from epoch
  
    return Math.abs(ageDate.getUTCFullYear() - 1970);
  }
  
  function setCurrentYear() {
    document.querySelector('#current_year').innerHTML = new Date().getFullYear();
  }
  
  document.addEventListener('DOMContentLoaded', setBirthDate);
  document.addEventListener('DOMContentLoaded', setCurrentYear);
  