[danik.js]

В общем чета типа:

function EventEmmiter() {
   
}

// ... реализуем интерфейс EventEmmiter

/*
 * @inherits EventEmmiter
 *
 */
function Controller() {
    EventEmitter.call(this);
}

Controller.prototype = Object.create(EventEmitter.prototype, {
    constructor: {value: Controller}
});

Controller.prototype.updateDiv = function() {
    utils.request('some/url', this.onDivContentLoaded.bind(this));
};

Controller.prototype.onDivContentLoaded = function(data) {
    document.querySelector('div').innerHTML = data;
    this.dispatchEvent('divupdated', {data: data});
};



var controller = new Controller();

controller.addEventListener('divupdated', function() {
    alert('Div was updated');
});

controller.updateDiv();