How use javascript serial number?

This should do it:

function getNext[num] {
    var alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZ";
    var digits = num.toUpperCase[].split[""],
        len = digits.length,
        increase = true;
    if [len != 3]
        throw new Error["Invalid serial number length in getNext: "+num];
    for [var i=len-1; increase && i>=0; i--] {
        var val = alphabet.indexOf[digits[i]];
        if [val == -1]
            throw new Error["Invalid serial number digit in getNext: "+num];
        val++;
        if [val < alphabet.length] {
            digits[i] = alphabet[val];
            increase = false;
        } else { // overflow
            digits[i] = alphabet[0];
        }
    }
    if [increase] // is still true
        throw new Error["Serial number overflow in getNext"];
    num = digits.join[""];
    return num;
}

Since you are working with a nearly alphanumeric alphabet, a parseInt/toString with radix 33 might have done it as well. Only you need to "jump" over the 0, I and O, that means replacing 0,A,B… by A,B,C…, replacing H,I,J… by J,K,L… and replacing M,N,O… by P,Q,R… [and everything back on deserialisation] - which might be OK if JS has a numeric char datatype, but I think it's easier to do it manually as above.

If you're curious:

String.prototype.padLeft = function[n, x] {
     return [new Array[n].join[x || "0"]+this].slice[-n];
};
function getNext[num] {
    var alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZ";
    var back = {}, forth = {};
    for [var i=0; i