function checkFields()
{
  missinginfo = "";

  if (document.form.naam.value == "")
    missinginfo += "\n     - Name";

  if ((document.form.adres.value == "") || (document.form.adres.value.indexOf('@') == -1) || (document.form.adres.value.indexOf('.') == -1))
    missinginfo += "\n     - Email address";

  if (document.form.onderwerp.value == "")
    missinginfo += "\n     - Subject";

  if (document.form.tekst.value == "")
    missinginfo += "\n     - Text";

  if (missinginfo == "")
    return(true);

  alert("You failed to *correctly* fill in your:\n" +
        missinginfo + "\n" +
        "\n" +
        "Please re-enter and send again!");
  return(false);
}