TW perosnal id validator, 身份證字號檢查

gistfile1.js

//身份證字號檢查
function isValid(id) {
    return typeof id === 'string' && id.match(/^[a-z][12][0-9]{8}$/i) && (function(id) {
        var hash = [1, 10, 19, 28, 37, 46, 55, 64, 39, 73, 82, 2, 11, 20, 48, 29, 38, 47, 56, 65, 74, 83, 21, 3, 12, 30][id.charCodeAt(0) - 65];
        for (var i = 1; i < 9; i++) {
            hash += (9 - i) * (id.charCodeAt(i) - 48);
        }
        return (hash + id.charCodeAt(9) - 48) % 10 === 0;
    })(id);
}