JavaScript closure and the this object

Question

I thought I had a reasonable understanding of the this object in JavaScript. When dealing with objects, callbacks, and both events and handlers, I haven\'t had

Answer 1

The value of this depends only on whether you call the function as a method or as a function.

If you call it as a method, this will be the object that the method belongs to:

obj.myFunction();

If you call it as a function, this will be the window object:

myFunction();

Note that even if you are in a method that belongs to an object, you still have to call other methods in the object using the method syntax, otherwise they will be called as functions:

this.myOtherFunction();

If you put a method reference in a variable, you will detach it from the object, and it will be called as a function:

var f = obj.myFunction;
f();

The call and apply methods are used to call a function as a method even if it's not a method in the object (or if it's a method in a different object):

myFunction.call(obj);