function alertValidIBAN(iban) {
alert(isValidIBANNumber(iban));
}
/*
* Returns 1 if the IBAN is valid
* Returns FALSE if the IBAN's length is not as should be (for CY the IBAN Should be 28 chars long starting with CY )
* Returns any other number (checksum) when the IBAN is invalid (check digits do not match)
*/
function isValidIBANNumber(input) {
var CODE_LENGTHS = {
AD: 24, AE: 23, AT: 20, AZ: 28, BA: 20, BE: 16, BG: 22, BH: 22, BR: 29,
CH: 21, CR: 21, CY: 28, CZ: 24, DE: 22, DK: 18, DO: 28, EE: 20, ES: 24,
FI: 18, FO: 18, FR: 27, GB: 22, GI: 23, GL: 18, GR: 27, GT: 28, HR: 21,
HU: 28, IE: 22, IL: 23, IS: 26, IT: 27, JO: 30, KW: 30, KZ: 20, LB: 28,
LI: 21, LT: 20, LU: 20, LV: 21, MC: 27, MD: 24, ME: 22, MK: 19, MR: 27,
MT: 31, MU: 30, NL: 18, NO: 15, PK: 24, PL: 28, PS: 29, PT: 25, QA: 29,
RO: 24, RS: 22, SA: 24, SE: 24, SI: 19, SK: 24, SM: 27, TN: 24, TR: 26,
AL: 28, BY: 28, CR: 22, EG: 29, GE: 22, IQ: 23, LC: 32, SC: 31, ST: 25,
SV: 28, TL: 23, UA: 29, VA: 22, VG: 24, XK: 20
};
var iban = String(input).toUpperCase().replace(/[^A-Z0-9]/g, ''), // keep only alphanumeric characters
code = iban.match(/^([A-Z]{2})(\d{2})([A-Z\d]+)$/), // match and capture (1) the country code, (2) the check digits, and (3) the rest
digits;
// check syntax and length
if (!code || iban.length !== CODE_LENGTHS[code[1]]) {
return false;
}
// rearrange country code and check digits, and convert chars to ints
digits = (code[3] + code[1] + code[2]).replace(/[A-Z]/g, function (letter) {
return letter.charCodeAt(0) - 55;
});
// final check
return mod97(digits) === 1;
}
function mod97(string) {
var checksum = string.slice(0, 2), fragment;
for (var offset = 2; offset < string.length; offset += 7) {
fragment = String(checksum) + string.substring(offset, offset + 7);
checksum = parseInt(fragment, 10) % 97;
}
return checksum;
}