function enable_price()
{
  $('price').disabled = false;
  $('mortgage_type_eur').checked = false;
  $('mortgage_type_usd').checked = false;
  $('mortgage').disabled = true;
}

function enable_mortgage()
{
  $('price_type_eur').checked = false;
  $('price_type_usd').checked = false;
  $('price').disabled = true;
  $('mortgage').disabled = false;
}