// check for valid characters

function validString (stringa)
{
	var len=stringa.length;
	for(i=0;i<len;i++) 
	{
		carAscii = stringa.charCodeAt(i);
		if (!(carAscii==10 || carAscii==13 || carAscii >=32))
		{
			return false;
		}
	}
	return true;
}



// check for digits

function isDigit(car)
{
	if ((car< '0') || (car > '9')) 
		return false;
  else 
		return true;
}



// check for letteres

// ******************

function isLetter(car) {

  if ((car< 'A') || (car > 'Z')) 

    return false;

  else 

    return true;

}



//check if a string is a valid integer

// *************************************

function validNumber(txt) {

  var i;

  if (txt.length == 0)

    return true;

  for (i=0; i<txt.length; i++)

    if (!(isDigit(txt.charAt(i)))) 

      return false;

  return true;

}



// check if a string is an e-mail address

// *************************************

function validEMail(txt) {

  if (txt.indexOf('@') == -1) {

    return false;

  }

  txt=txt.toUpperCase();

  var i;

  for (i=0; i<txt.length; i++) {

    if (!(isDigit(txt.charAt(i)) || isLetter(txt.charAt(i)) || (txt.charAt(i) == '_') || (txt.charAt(i) == '-') || (txt.charAt(i) == '.') || (txt.charAt(i) == '@'))) {

      return false;

    }

  }

  return true;

}





// verifica il pagamento in contrassegno

// *************************************

function isContrassegno(what) {

    if ((what.value.length > 0) && (what.pagamento[2].checked)) {

    return true;

  }

  else

  {

    return false;

}

}