function validate_form()
{
  valid = true;
  missing = "";
  warning = "#ff0000";
  normal = "#ffffff";

  //
  // Name
  //
  if (document.contact.name.value == "")
  {
    missing = missing +"\nName";
    valid = false;
    document.contact.name.style.backgroundColor = warning;
  }
  else
  {
    document.contact.name.style.backgroundColor = normal;
  }


  //
  // E-Mail
  //
  if (document.contact.email.value == "")
  {
    missing = missing +"\nE-Mail";
    valid = false;
    document.contact.email.style.backgroundColor = warning;
  }
  else
  {
    document.contact.email.style.backgroundColor = normal;
  }


  //
  // Message
  //
  if (document.contact.message.value == "")
  {
    missing = missing +"\nMessage";
    valid = false;
    document.contact.message.style.backgroundColor = warning;
  }
  else
  {
    document.contact.message.style.backgroundColor = normal;
  }

  if (valid == false)
  {
    alert ("You have not filled out the following information, which is required.\n" + missing);
  }
  return valid;
}