oop.js

function extend(source, obj) {
    for(var key in obj) {
        if((obj[key].constructor === Array || typeof obj[key] !== "object") && obj.hasOwnProperty(key)) {
            source[key] = obj[key];
        } else {
            source[key] = extend(source[key]||{}, obj[key]);
        }
    }
    return source
}


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

A.prototype.toString = function() {
    return "A: "+this.name;
};

function B(name) {
    B.prototype.parent.apply(this, [name]);
}

B.prototype = extend(new A, {
    parent: A,
    constructor: B,
    toString: function() {
        return "B: "+this.name;
    }
});

function C(name) {
    C.prototype.parent.apply(this, [name]);
}

C.prototype = extend(new B, {
    parent: B,
    constructor: C,
    toString: function() {
        return "C: "+this.name;
    }
});