constructor.name is undefined in Internet Explorer

Question

My debugging work in IE ended today by finding that constructor.name is undefined.

I created the following simple code that reproduces the issu

Answer 1

Perhaps this example clears up some confusion.

var number = 10;        //A global variable. Part of the global window object.
//window.number = 10;   //Does exactly the same as the line above.


var customer = {
    number: 20,
    speak: function () {
        if (this === window) {
            alert('I am being called by go() ' + this.number);      //this.number points to the global variable number
        } else {
            alert('I am being called by customer.speak ' + this.number);  //this.number points to the customer member number
        }
    }
}

var go = customer.speak;  //Go now points directly to the function called "speak" as if it is not a part of the customer object. The this parameter of speak will be the global window object;

go();
customer.speak();         //Now the speak function is called a part of the customer object. The this parameter of speak will be the customer object