function checkSberatel(form) {
  if (!form.firma.value) { alert("Please fill-in 'Company' field!"); form.firma.focus(); return false; }
  if (!form.jmeno.value) { alert("Please fill-in 'Name' field!"); form.jmeno.focus(); return false; }
  if (!form.prijmeni.value) { alert("Please fill-in 'Surname' field!"); form.prijmeni.focus(); return false; }
  if (!form.ulice.value) { alert("Please fill-in 'Street' field!"); form.ulice.focus(); return false; }
  if (!form.mesto.value) { alert("Please fill-in 'City' field!"); form.mesto.focus(); return false; }
  if (!form.psc.value) { alert("Please fill-in 'Postcode/ZIP' field!"); form.psc.focus(); return false; }
  if (!form.zeme.value) { alert("Please fill-in 'Country' field!"); form.zeme.focus(); return false; }
}

function checkUbytovani(form) {
  if (!form.firma.value) { alert("Please insert 'Company'"); form.firma.focus(); return false; }
  if (!form.adresa.value) { alert("Please insert 'Address'"); form.adresa.focus(); return false; }
  if (!form.kontakt.value) { alert("Please insert 'Contact person'"); form.kontakt.focus(); return false; }
}