quick timer implementation, also good demo of clojure

timer

function Timer(callback, delay) {
    if (!isNaN(delay) && callback) {
        if (delay < 1000) delay = 1000;

        this.delay = delay;
        this.callback = callback;

        var running = false;

        this.ticker = function (a) {
            a.callback.call(a);
        };

        this.pause = function () {
            if (running) {
                window.clearInterval(this.timerId);
                running = false;
            }
        };

        this.resume = function () {
            if (!running) {
                this.timerId = window.setInterval(this.ticker, this.delay, this);
                running = true;
            }
        };

        this.resume();
    }

    return this;
};

count = 0;
var timer = new Timer(function () {
    console.log('count - ' + count);
    if (count > 3) {
        this.pause();
    } else {
        count++;
    }
}, 1);