JavaScript inheritance: Uncaught RangeError: Maximum call stack size exceeded

In trying to port a Java app to JavaScript, I'm attempting the following inheritance technique:

var grandchild = new Grandchild();

Function.prototype.extend =
    function(parent) {
        var parentPrototype = parent.prototype;
        this.prototype = Object.create(parentPrototype);
        this.prototype.superPrototype = parentPrototype;
        this.prototype.superConstructor = parent;
        this.prototype.constructor = this;
    }
;

function Parent(){
    this.doStuff();
}

Parent.prototype.doStuff =
    function() {
    }
;

Child.extend(Parent);
function Child(){
    this.superConstructor.call(this);
}

Child.prototype.doStuff = function() {
    this.superPrototype.doStuff.call(this);
}

Grandchild.extend(Child);
function Grandchild(){
    this.superConstructor.call(this);
}

Grandchild.prototype.doStuff = function() {
    this.superPrototype.doStuff.call(this);
}

It works to one level of inheritance (i.e. var child = new Child()) but with new Grandchild() it throws an Uncaught RangeError: Maximum call stack size exceeded because it gets stuck in infinite recursion on function Child().

1. What exactly is happening and why?
2. How can I tweak this technique so it allows me to call this.superConstructor.call(this) and this.superPrototype.doStuff.call(this) as shown without hitting the infinite recursion on the immediate parent?

It works when I specify the super class in the calls as follows, but I would prefer not to have to do this:

function Child(){
    Parent.call(this);
}

Child.prototype.doStuff = function() {
    Parent.prototype.doStuff.call(this);
}

function Grandchild(){
    Child.call(this);
}

Grandchild.prototype.doStuff = function() {
    Child.prototype.doStuff.call(this);
}