Object oriented Javascript: event handling

I'm trying to create an event for an object to have it listen to it. Consider the following example:

var moon;

moon = document.createEvent("Event");
moon.initEvent("Event",true,true);

var Dog = function (name) {
  this.name = name;
  
  document.addEventListener("Event",this.bark,false);
};
dog.prototype.bark = function() {
  console.log(this.name + ': Awooooooof Woof!');
};


var spot = new Dog("Spot");
var dot = new Dog("Dot");


//invoke
document.dispatchEvent(moon);

I'm expecting to receive an output like:

Spot: Awooooooof Woof!

Dot: Awooooooof Woof!

But what I get is:

undefined: Awooooooof Woof!

What is wrong with my example? How can I register a listener that every instance of Dog has?