Question

my code :

var n;
function f(){
   var v = "kevin";
   n = function(){
      return v;
   }
}

execute in FireBug:
n();
the result is “kevin”

execute in Chrome & IE9:

document.writeln(n); ======>show “undefine”
document.writeln(n()); ======>show nothing

I want to know what exactly the brows doing when execute the code.
Thanks.

That code is a demo of the book “Object Oriented JavaScript”, Chapter 3, Closure 2#

Answer 1

The variable n is not given a value (i.e., is not assigned to that function) until the function f() has been executed – which doesn’t happen in the code you show.

So document.writeln(n); should show “undefined”, while document.writeln(n()); should be an error since n is not a function.

I don’t know why it works in FireBug – have you already executed f() when you try it?