this value in JavaScript anonymous function

Question

Can anybody explain to me why A is true and B is false? I would have expected B to be true as well.

function MyObject() {

};

MyOb         


        

Answer 1

In the anonymous function, this is bound to the global object (window in a browser environment).

There are various ways of accessing the instance:

var self = this;
(function () {
    console.log("B", self instanceof MyObject);
}());

or

(function () {
    console.log("B", this instanceof MyObject);
}).call(this);