JavaScript prototypes example

ojs-prototypes.js

function GreatDane() { }

var rover = new GreatDane();
var spot = new GreatDane();

GreatDane.prototype.getBreed = function() {
    return "Great Dane";
};

// Works, even though at this point
// rover and spot are already created.

alert(rover.getBreed());

// this hides getBreed() in GreatDane.prototype
spot.getBreed = function() {
    return "Little Great Dane";
};

alert(spot.getBreed()); 

// but of course, the change to getBreed 
// doesn’t propagate back to GreatDane.prototype
// and other objects inheriting from it,
// it only happens in the spot object

alert(rover.getBreed());