function EMail(s){
 var a = false;
 var res = false;
 if(typeof(RegExp) === 'function') {
  var b = new RegExp('abc');
  if(b.test('abc') === true){
   a = true;
  }
 }
 if(a === true){
  reg = new RegExp('^([a-zA-Z0-9\\-\\.\\_]+)'+'(\\@)([a-zA-Z0-9\\-\\.]+)'+'(\\.)([a-zA-Z]{2,4})$');
  res = (reg.test(s));
 } else {
  res = (s.search('@') >= 1 && s.lastIndexOf('.') > s.search('@') && s.lastIndexOf('.') >= s.length-5);
 }
 return(res);
}

/* Kontaktformular */
function chk_contact(formul){
 formul.name.className = "gastbuch_text";
 formul.mail.className = "gastbuch_text";
 formul.text.className = "gastbuch_textarea";
 formul.numero_sicurezza.className = "gastbuch_text";
 var ok = true;
 if(formul.name.value === ""){
  ok = false;
  formul.name.className = "gastbuch_text_error";
 }
 if(!EMail(formul.mail.value)){
  ok = false;
  formul.mail.className = "gastbuch_text_error";
 }
 if(formul.text.value === ""){
  ok = false;
  formul.text.className = "gastbuch_textarea_error";
 }
 if(formul.numero_sicurezza.value.length !== 6){
  ok = false;
  formul.numero_sicurezza.className = "gastbuch_text_error";
 }
 if(ok){
  return true;
 } else {
  alert("Felder Kontrollieren!");
  return false;
 }
}