JavaScript prototype inheritance.

gistfile1.js

function Animal(name) {
    this.ssname = name;
    console.log("Animal ctor", arguments);
}

Animal.prototype.walk = function() {
    console.log("Animal walks", this.ssname);
}

Cat.prototype = new Animal();
Cat.prototype.constructor = Cat;

function Cat(name){ 
    Animal.apply(this, arguments);
    console.log("Cat ctor", arguments);
}

Cat.prototype.walk = function() {
    console.log("Cat walks", this.ssname);
    Animal.prototype.walk.call(this);
}


var a = new Cat("darwin");
var b = new Cat("james");

a.walk();
b.walk();