Question

I have a function which takes a callback function. How can I set the ‘this’ variable of the callback function?

eg.

function(fn){
    //do some stuff
    fn(); //call fn, but the 'this' var is set to window
    //, how do I set it to something else
}

Answer 1

you can execute a function in the context of an object using call:

fn.call( obj, 'param' )

There’s also apply

Only difference is the syntax for feeding arguments.