function cancelAction (evt) {
  return false;
}
function disableSubmitButton (button) {
  if (typeof button.disabled != 'undefined')
    button.disabled = true;
  else if (!button.buttonDisabled) {
    button.oldValue = button.value;
    button.oldOnclick = button.onclick;
    button.value = 'DISABLED';
    button.onclick = cancelAction;
    button.buttonDisabled = true;
  }
}
function enableSubmitButton (button) {
  if (typeof button.disabled != 'undefined')
    button.disabled = false;
  else if (button.buttonDisabled) {
    button.value = button.oldValue;
    button.onclick = button.oldOnclick;
    button.buttonDisabled = false;
  }
}