function formChk(){
  	missing = "";
  	form = document.getElementById("scheda");
  	if (form.nome.value == "")
  		missing += "'Name' field is required\n";
  	if (form.cognome.value == "")
  		missing += "'Surname' field is required\n";
  	if (form.mail.value == "" && form.tel.value == "")
  		missing += "at least one of 'Email' or 'Phone' fields is required\n";
  	if (missing != ""){
  		error_msg = "Attention! Marked fields are required:\n\n" + missing;
  		window.alert (error_msg);
  		return false;
  	}
	return true;
}