inheritance.js

function A(x) { this.x = x; };

function B(x,y) { A.call(this, x); this.y = y; };
B.prototype = new A();
B.prototype.what = function(){ return "hello"; };

var d = new B(5, 10);

A.prototype.say = function(){return "say " + this.what();};
B.prototype.say = function(){return ">> : " + A.prototype.say.call(this);};