Simple PubSub implementation with JavaScript - taken from Addy Osmani's design patterns book -

pubsub-simple.js

var pubsub = {};
(function(q) {
    var topics = {}, subUid = -1;
    q.subscribe = function(topic, func) {
        if (!topics[topic]) {
            topics[topic] = [];
        }
        var token = (++subUid).toString();
        topics[topic].push({
            token: token,
            func: func
        });
        return token;
    };

    q.publish = function(topic, args) {
        if (!topics[topic]) {
            return false;
        }
        setTimeout(function() {
            var subscribers = topics[topic],
                len = subscribers ? subscribers.length : 0;

            while (len--) {
                subscribers[len].func(topic, args);
            }
        }, 0);
        return true;

    };

    q.unsubscribe = function(token) {
        for (var m in topics) {
            if (topics[m]) {
                for (var i = 0, j = topics[m].length; i < j; i++) {
                    if (topics[m][i].token === token) {
                        topics[m].splice(i, 1);
                        return token;
                    }
                }
            }
        }
        return false;
    };
}(pubsub));