function isNumberKey(evt)
{
var charCode = (evt.which) ? evt.which : event.keyCode
if (charCode > 31 && (charCode < 48 || charCode > 57))
  return false;
return true;
}

function isAllowedPass(evt)
{
var charCode = (evt.which) ? evt.which : event.keyCode
if (charCode > 31 && (charCode < 48 || charCode > 57) && (charCode < 65 || charCode > 90) && (charCode < 97 || charCode > 122))
  return false;
return true;

}

function darkBack(id) {
	document.getElementById (id).className = "katalog_item_dark";
}
function lightBack(id) {
	document.getElementById (id).className = "katalog_item";
}
function darkBackRight(id) {
	document.getElementById (id).className = "katalog_item_right_dark";
}
function lightBackRight(id) {
	document.getElementById (id).className = "katalog_item_right";
}

function kontrola_emailu(email) {
  re = /^[^.]+(.[^.]+)*@([^.]+[.])+[a-z]{2,3}$/;
  return email.search(re) == 0;
}

function check_form_objednavka(f) {
  var error = '';
  if ((error == '') && (f.jmeno.value == '')) { error = 'Zadejte jméno'; }
  if ((error == '') && (f.prijmeni.value == '')) { error = 'Zadejte přijmení'; }
  if ((error == '') && (f.firma.value == '')) { error = 'Zadejte název firmy'; }
  if ((error == '') && (f.adresa.value == '')) { error = 'Zadejte adresu'; }
  if ((error == '') && (f.email.value == '')) { error = 'Zadejte e-mail'; }
  if ((error == '') && (f.email.value != '') && (!kontrola_emailu(f.email.value))) { error = 'Zadaný e-mail nemá správný tvar'; }
  if ((error == '') && (f.telefon.value == '')) { error = 'Zadejte telefon'; }
  if ((error == '') && (document.getElementById('jsem_odberatel_ano').checked == false) && (document.getElementById('jsem_odberatel_ne').checked == false)) { error = 'Uveďte zda jste odběratel'; }
  if (error != '') {
    alert(error);
    return false;
  }
  return true;
}

function check_form_objednavka_en(f) {
  var error = '';
  if ((error == '') && (f.jmeno.value == '')) { error = 'Enter your name'; }
  if ((error == '') && (f.prijmeni.value == '')) { error = 'Enter your last name'; }
  if ((error == '') && (f.firma.value == '')) { error = 'Enter name of company'; }
  if ((error == '') && (f.adresa.value == '')) { error = 'Enter your address'; }
  if ((error == '') && (f.email.value == '')) { error = 'Enter your e-mail'; }
  if ((error == '') && (f.email.value != '') && (!kontrola_emailu(f.email.value))) { error = 'E-mail is not correct'; }
  if ((error == '') && (f.telefon.value == '')) { error = 'Enter your phone number'; }
  if ((error == '') && (document.getElementById('jsem_odberatel_ano').checked == false) && (document.getElementById('jsem_odberatel_ne').checked == false)) { error = 'Are you our customer yet?'; }
  if (error != '') {
    alert(error);
    return false;
  }
  return true;
}

function check_form_finding(f) {
  var error = '';
  if ((error == '') && (f.finded_text.value == '')) { error = 'Enter your searched aspect'; }
  if (error != '') {
    alert(error);
    return false;
  }
  return true;
}