function checkContactForm()
{
  if(document.getElementById('subject').value == '')
  {
    alert('Please choose a subject for this email.');
    return false;
  }
  if(document.getElementById('first_name').value == '')
  {
    alert('Please enter your first name.');
    document.getElementById('first_name').select();
    return false;
  }
  if(document.getElementById('last_name').value == '')
  {
    alert('Please enter your last name.');
    document.getElementById('last_name').select();
    return false;
  }
  if(document.getElementById('email_address').value == '')
  {
    alert('Please enter your email address.');
    document.getElementById('email_address').select();
    return false;
  }
  if(document.getElementById('comments').value == '')
  {
    alert('Please enter some comments.');
    document.getElementById('comments').select();
    return false;
  }
  return true;
}