Validate an ISSN using JavaScript
Last week I wrote about validating an ISBN, so this week I thought I would post the code to validate an ISSN.
There are only a few minor differences between validating an ISSN and ISBN.
function isValidISSN (issn) {
issn = issn.replace(/[^\dX]/gi, '');
if(issn.length != 8){
return false;
}
var chars = issn.split('');
if(chars[7].toUpperCase() == 'X'){
chars[7] = 10;
}
var sum = 0;
for (var i = 0; i < chars.length; i++) {
sum += ((8-i) * parseInt(chars[i]));
};
return ((sum % 11) == 0);
}