// Form Validation Functions  v1.1.6
// http://www.dithered.com/javascript/form_validation/index.html
// code by Chris Nott (chris@NOSPAMdithered.com - remove NOSPAM)


function getFormErrors(form) {
   var errors = new Array();

   // loop thru all form elements
   for (var elementIndex = 0; elementIndex < form.elements.length; elementIndex++) {
      var element = form.elements[elementIndex];

      // text and textarea types
      if (element.type == "text" || element.type == "textarea") {
         element.value = trimWhitespace(element.value)

         // required element
         if (element.required  && element.value == '') {
            errors[errors.length] = element.requiredError;
         }

         // maximum length
         else if (element.maxlength && isValidLength(element.value, 0, element.maxlength) == false) {
            errors[errors.length] = element.maxlengthError;
         }

         // minimum length
         else if (element.minlength && isValidLength(element.value, element.minlength, Number.MAX_VALUE) == false) {
            errors[errors.length] = element.minlengthError;
         }

         // pattern (credit card number, email address, alphanumeric, numeric)
         else if (element.pattern) {
            if ( ( (element.pattern.toLowerCase() == 'visa' || element.pattern.toLowerCase() == 'mastercard' || element.pattern.toLowerCase() == 'american express' || element.pattern.toLowerCase() == 'diners club' || element.pattern.toLowerCase() == 'discover' || element.pattern.toLowerCase() == 'enroute' || element.pattern.toLowerCase() == 'jcb' || element.pattern.toLowerCase() == 'credit card') && isValidCreditCard(element.value, element.pattern) == false) ||
                  (element.pattern.toLowerCase() == 'email' && isValidEmailStrict(element.value) == false) ||
                  (element.pattern.toLowerCase() == 'alphanumeric' && isAlphanumeric(element.value, true) == false) ||
                  (element.pattern.toLowerCase() == 'numeric' && isNumeric(element.value, true) == false) ||
                  (element.pattern.toLowerCase() == 'alphabetic' && isAlphabetic(element.value, true) == false) ) {
               errors[errors.length] = element.patternError;
            }
         }
      }

      // password
      else if (element.type == "password") {

         // required element
         if (element.required  && element.value == '') {
            errors[errors.length] = element.requiredError;
         }

         // maximum length
         else if (element.maxlength && isValidLength(element.value, 0, element.maxlength) == false) {
            errors[errors.length] = element.maxLengthError;
         }

         // minimum length
         else if (element.minlength && isValidLength(element.value, element.minlength, Number.MAX_VALUE) == false) {
            errors[errors.length] = element.minLengthError;
         }
      }

      // file upload
      if (element.type == "file") {

         // required element
         if (element.required  && element.value == '') {
            errors[errors.length] = element.requiredError;
         }
      }

      // select
      else if (element.type == "select-one" || element.type == "select-multiple" || element.type == "select") {

         // required element
         if (element.required && element.selectedIndex == -1) {
            errors[errors.length] = element.requiredError;
         }

		 // disallow empty value selection
         else if (element.disallowEmptyValue && element.options[element.selectedIndex].value == '') {
            errors[errors.length] = element.disallowEmptyValueError;
         }

      }

      // radio buttons
      else if (element.type == "radio") {
         var radiogroup = form.elements[element.name];

         // required element
         if (radiogroup.required && radiogroup.length) {
            var checkedRadioButton = -1;
            for (var radioIndex = 0; radioIndex < radiogroup.length; radioIndex++) {
               if (radiogroup[radioIndex].checked == true) {
                  checkedRadioButton = radioIndex;
                  break;
               }
            }
            if (checkedRadioButton == -1 && !radiogroup.tested) {
               errors[errors.length] = radiogroup.requiredError;
               radiogroup.tested = true;
            }
         }

         radiogroup = null;
      }
   }

	return errors;
}

// Check that the number of characters in a string is between a max and a min
function isValidLength(string, min, max) {
	if (string.length < min || string.length > max) return false;
	else return true;
}

// Check that a credit card number is valid based using the LUHN formula (mod10 is 0)
function isValidCreditCard(number) {
	number = '' + number;

	if (number.length > 16 || number.length < 13 ) return false;
	else if (getMod10(number) != 0) return false;
	else if (arguments[1]) {
		var type = arguments[1];
		var first2digits = number.substring(0, 2);
		var first4digits = number.substring(0, 4);

		if (type.toLowerCase() == 'visa' && number.substring(0, 1) == 4 &&
			(number.length == 16 || number.length == 13 )) return true;
		else if (type.toLowerCase() == 'mastercard' && number.length == 16 &&
			(first2digits == '51' || first2digits == '52' || first2digits == '53' || first2digits == '54' || first2digits == '55')) return true;
		else if (type.toLowerCase() == 'american express' && number.length == 15 &&
			(first2digits == '34' || first2digits == '37')) return true;
		else if (type.toLowerCase() == 'diners club' && number.length == 14 &&
			(first2digits == '30' || first2digits == '36' || first2digits == '38')) return true;
		else if (type.toLowerCase() == 'discover' && number.length == 16 && first4digits == '6011') return true;
		else if (type.toLowerCase() == 'enroute' && number.length == 15 &&
			(first4digits == '2014' || first4digits == '2149')) return true;
		else if (type.toLowerCase() == 'jcb' && number.length == 16 &&
			(first4digits == '3088' || first4digits == '3096' || first4digits == '3112' || first4digits == '3158' || first4digits == '3337' || first4digits == '3528')) return true;

    // if the above card types are all the ones that the site accepts, change the line below to 'else return false'
    else return true;
	}
	else return true;
}

// Check that an email address is valid based on RFC 821 (?)
function isValidEmail(address) {
	if (address != '' && address.search) {
      if (address.search(/^\w+((-\w+)|(\.\w+))*\@[A-Za-z0-9]+((\.|-)[A-Za-z0-9]+)*\.[A-Za-z0-9]+$/) != -1) return true;
      else return false;
	}

   // allow empty strings to return true - screen these with either a 'required' test or a 'length' test
   else return true;
}

// Check that an email address has the form something@something.something
// This is a stricter standard than RFC 821 (?) which allows addresses like postmaster@localhost
function isValidEmailStrict(address) {
	if (isValidEmail(address) == false) return false;
	var domain = address.substring(address.indexOf('@') + 1);
	if (domain.indexOf('.') == -1) return false;
	if (domain.indexOf('.') == 0 || domain.indexOf('.') == domain.length - 1) return false;
	return true;
}

// Check that a string contains only letters and numbers
function isAlphanumeric(string, ignoreWhiteSpace) {
	if (string.search) {
		if ((ignoreWhiteSpace && string.search(/[^\w\s]/) != -1) || (!ignoreWhiteSpace && string.search(/\W/) != -1)) return false;
	}
	return true;
}

// Check that a string contains only letters
function isAlphabetic(string, ignoreWhiteSpace) {
	if (string.search) {
		if ((ignoreWhiteSpace && string.search(/[^a-zA-Z\s]/) != -1) || (!ignoreWhiteSpace && string.search(/[^a-zA-Z]/) != -1)) return false;
	}
	return true;
}

// Check that a string contains only numbers
function isNumeric(string, ignoreWhiteSpace) {
	if (string.search) {
		if ((ignoreWhiteSpace && string.search(/[^\d\s]/) != -1) || (!ignoreWhiteSpace && string.search(/\D/) != -1)) return false;
	}
	return true;
}

// Remove characters that might cause security problems from a string
function removeBadCharacters(string) {
	if (string.replace) {
		string.replace(/[<>\"\'%;\)\(&\+]/, '');
	}
	return string;
}

// Remove all spaces from a string
function removeSpaces(string) {
	var newString = '';
	for (var i = 0; i < string.length; i++) {
		if (string.charAt(i) != ' ') newString += string.charAt(i);
	}
	return newString;
}

// Remove leading and trailing whitespace from a string
function trimWhitespace(string) {
	var newString  = '';
	var substring  = '';
	beginningFound = false;

	// copy characters over to a new string
	// retain whitespace characters if they are between other characters
	for (var i = 0; i < string.length; i++) {

		// copy non-whitespace characters
		if (string.charAt(i) != ' ' && string.charCodeAt(i) != 9) {

			// if the temporary string contains some whitespace characters, copy them first
			if (substring != '') {
				newString += substring;
				substring = '';
			}
			newString += string.charAt(i);
			if (beginningFound == false) beginningFound = true;
		}

		// hold whitespace characters in a temporary string if they follow a non-whitespace character
		else if (beginningFound == true) substring += string.charAt(i);
	}
	return newString;
}

// Returns a checksum digit for a number using mod 10
function getMod10(number) {

	// convert number to a string and check that it contains only digits
	// return -1 for illegal input
	number = '' + number;
	number = removeSpaces(number);
	if (!isNumeric(number)) return -1;

	// calculate checksum using mod10
	var checksum = 0;
	for (var i = number.length - 1; i >= 0; i--) {
		var isOdd = ((number.length - i) % 2 != 0) ? true : false;
		digit = number.charAt(i);

		if (isOdd) checksum += parseInt(digit);
		else {
			var evenDigit = parseInt(digit) * 2;
			if (evenDigit >= 10) checksum += 1 + (evenDigit - 10);
			else checksum += evenDigit;
		}
	}
	return (checksum % 10);
}


function isNif(val){
 if (val.length == 0)
  return false;

 // Letra recibida
 var letra = val.charAt(val.length - 1);

 // definir el array de letras
 var nif_letras = "TRWAGMYFPDXBNJZSQVHLCKEU"

 var res = parseInt(val, 10);

 var pos = (parseInt(res) - Math.floor(parseInt(res)/23) * 23) + 1;
 var n_letra = nif_letras.substring(pos - 1, pos);

 return n_letra == letra;

}