function setButtonsState(parent, enable)
{
  $(parent).select("span.button" + (enable ? "-disabled" : "")).each(enable ? enableButton : disableButton);
}

function disableButton(btn)
{
  if(btn.className == "button-disabled") return;
  btn.className = "button-disabled";
  btn.onclickSaved = btn.onclick;
  btn.onclick = "";
}

function enableButton(btn)
{
  if(btn.className == "button") return;
  btn.className = "button";
  btn.onclick = btn.onclickSaved;
}