Here is the code

```
function Person(name, age, weight) {
    this._name = name;
    this._weight = weight;
    this._age = age;
}

Person.prototype = {
    Anatomy: {
        Weight: this._weight,
        Height: (function () {
            //calculate height from age and weight
        })
    }
}

```

i expected `Anatomy.weight` to be 60 when i ran this code:

```
var x = new Person('jack',24,60);
console.dir(x.Anatomy);

```

To my surprise it was undefined. On inspection it seemed that `this` was referring to global object window. Now what has happened here :(
I expected `this._weight` to refer Person objects weight, otherwise from rough calculation, this should have at the least referred to Anatomy since it is a object. Could someone clarify the doubt