function validate_form ( )
{ valid = true; 
  if ( document.login.user.value == "" )
  { alert ( "Anda belum mengisi Username" ); valid = false; }
  if ( document.login.pass.value == "" )
  { alert ( "Anda belum mengisi Password" ); valid = false; }
  if ( document.login.number.value == "" )
  { alert ( "Anda belum mengisi Anti Spam" ); valid = false; }
  return valid;
}