function validateContactForm(form)
{ if (form.fullName.value == "")
  { alert("Please enter your name.");
    return false;
  }

  if (form.email.value != "")
  { if (form.email.value.indexOf("@") == -1 || form.email.value.indexOf(".") == -1 || form.email.value.indexOf(" ") != -1 || form.email.value.length < 6)
    { alert("Sorry, the email address does not appear to be valid.");
      return false;
    }
  }

  if (form.email.value == "")
  { alert("Please enter your email address.");
    return false;
  }
}