function validate() {
  var fail = 0;
  document.getElementById('warningFirstName').innerHTML = '';
  document.getElementById('warningLastName').innerHTML = '';
  document.getElementById('warningPhone').innerHTML = '';

  if (document.getElementById('contact').firstName.value == '') {
    document.getElementById('warningFirstName').innerHTML = 'First name is required';
    fail = 1;
  }

  if (document.getElementById('contact').lastName.value == '') {
    document.getElementById('warningLastName').innerHTML = 'Last name is required';
    fail = 1;
  }

  var phoneFilter = /\(?\d{3}\)?[\-,\., ]?\d{3}[\-,\., ]?\d{4}/;
  var phone = document.getElementById('contact').phone.value;
  if (!phone.match(phoneFilter)) {
    document.getElementById('warningPhone').innerHTML = 'Valid phone number is required';
    fail = 1
  }

  if (fail == 1) {
    return false;
  }
  return true;
}