javascript - using apply to pass in an object for the this keyword -

I'm trying to teach myself Javascript, but I think it's stuck on a basic basis. My reference book says:

" This can be applied to pass in an object to indicate the keyword."

I start with:

  var a = 50; Var foo = function () {return.a; }

When I do foo () , then I would like 50 then I apply Try as follows:

  foo.apply ({a: "blah"});

When I do foo () again, I still get 50 and blah was not as expected.

It appears that apply was not successful in the keyword {a: "blah"} objects .

I am almost certain that I am misunderstood what can help you with explanation?

apply () method does not modify function by any means; It only makes a function call with the specified it .

You can use bind () to create a new function, which always calls the original with the specified this :

  var myFoo = foo.bind ({a: 'blah'}); MyFoo ();

Alcantara