Running javascript processes in background with node.js

Update: I learned about Task object, and I managed to put an intensive process in Javascript in background, keeping Max very responsive. That's my js code:

var possiblePrime = 2; // to start test of prime numbers
var tick = function () {
    arguments.callee.task.schedule(0);
    findPrimes();
}
var clock = new Task(tick, this, 0);
function start() {
    clock.execute();
}
function stop() {
    clock.cancel();
}
function msg_int(v) {
    possiblePrime = v;
    clock.execute();
}
// really unoptimized and costly function to find prime numbers
function findPrimes() {
    var isPrime = true;
    for (var n = 2; n < possiblePrime; n++) {
        if (possiblePrime % n == 0) {
            isPrime = false;
        }
    }
    if (isPrime) {
        post(possiblePrime + "\n");
        outlet(0, possiblePrime);
    }
    possiblePrime++;
}

I suspect this continuous background processes could be strongly optimized, so any advices or improvements will be highly appreciated.
jlm