/////////////////////////////////////////////////////////////

function submit_check(f) {
  if (f.name.value == '') {
    alert ("Please enter your name.");
    f.name.focus();
    return false;
  }

  if (f.email.value == '') {
    alert ("Please enter your proper email address.");
    f.email.focus();
    return false;
  }

  if (f.phone.value == '') {
    alert ("Please enter your telephone number.");
    f.phone.focus();
    return false;
  }

  return true;
}