Passing a function as argument

Question

Here is my exemple :

function a(b)
{
    b();
}

function b()
{
    alert("d");
}

function c()
{
    alert("e");
}

a(c);//Output e

With the fiddle : http://jsfiddle.net/YqeS3/

How can I fire the real b function from a?

local variables trump global variables, use a better naming convention. :) — epascarello, Jun 05 '12 at 12:09
yes, this questions makes no sense. What you're doing is shadowing a variabile – that often comes to bug hard to find. — ZER0, Jun 05 '12 at 12:12

score 1 · Answer 1 · answered Jun 05 '12 at 12:06

1

If all of these functions are defined on the global scope you can use this:

window.b();

answered Jun 05 '12 at 12:06

Sirko

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Good... but can I do something equivalent if `b` is not global? – user1365010 Jun 05 '12 at 12:08
Ahh, then you are out of luck. See about _shadowing in JavaScript_ [here](http://stackoverflow.com/questions/5373278/variable-shadowing-in-javascript) – Alexander Pavlov Jun 05 '12 at 12:11

score 1 · Accepted Answer · answered Jun 05 '12 at 12:12

If your B function isn't global, and you don't want to use naming conventions, you could create an additional function

function d() {
    b();
}

and call that one instead. I still think that you should simply name your argument and your function something else though, as it'd also create much less confusion for any other person (this include the future version of yourself) looking at your code.

score 0 · Answer 3 · answered Jun 05 '12 at 12:07

0

You can call it by two methods

b();

a(b);

answered Jun 05 '12 at 12:07

Miqdad Ali

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score 0 · Answer 4 · answered Jun 05 '12 at 12:08

0

Presuming that you need to call the real function b from a, you should write:

window.b();

answered Jun 05 '12 at 12:08

Alexander Pavlov

31,598
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score 0 · Answer 5 · answered Jun 05 '12 at 12:14

The variable b in your function a is just a local variable which you can name whatever you like. Calling it b within the scope of a will make you unable to call external variables or functions with that name within the functions scope. As answered before here by Sirko, you can call outside the functions scope by the use of the

window.b();

Consider renaming your scoped variables if you have problems.

Passing a function as argument

5 Answers5