function tabulka()
{
 if (document.getElementById("customers_dd").checked){document.getElementById("nadpis_tabulky").style.display="block";document.getElementById("tabulka").style.display="block";}
 if (!document.getElementById("customers_dd").checked){document.getElementById("nadpis_tabulky").style.display="none"; document.getElementById("tabulka").style.display="none";}
}