function validateAppointment()
{
  var nameInput = document.getElementById('appointmentName');
  var phoneInput = document.getElementById('appointmentPhone');
  var rtn = true;
  
  if (nameInput && phoneInput)
  {
    if (nameInput.value == '')
    {
      nameInput.className = 'form_element_error';
      document.getElementById('appointmentNameError').style.display='block';
      rtn = false;
    }
    else if (nameInput.className == 'form_element_error')
    {
      nameInput.className = 'form_element';
      document.getElementById('appointmentNameError').style.display='none';
    }
    
    if (phoneInput.value == '')
    {
      phoneInput.className = 'form_element_error';
      document.getElementById('appointmentPhoneError').style.display='block';
      rtn = false;
    }
    else if (phoneInput.className == 'form_element_error')
    {
      phoneInput.className = 'form_element';
      document.getElementById('appointmentPhoneError').style.display='none';
    }
  }
  
  return rtn;
}