jsObservables

var observableText = {
    observers: [],
    text: "",
    notifyAll: function(o){
        for (var j = 0; j < this.observers.length; j++){
          this.observers[j].update(this.text);
        }
    },
    addObserver: function(o){
        this.observers.push(o);
    },
    updateText: function(t){
        this.text = t;
        this.notifyAll();
    }
};

var displayText = {
    text: "",
    update: function(t){
        this.text = t;
        console.log(this.text);
    }
}
observableText.addObserver(displayText);
observableText.updateText("updated once");
observableText.updateText("updated twice");