What (function(){})(); mean?

Question

Possible Duplicate:
What does this “(function(){});”, a function inside brackets, mean in javascript ?

(function(){
    ---this code at here ----
})();

What does (function(){})(); mean? Please explain it to me.

duplicate: http://stackoverflow.com/questions/4043647/what-does-this-function-a-function-inside-brackets-mean-in-javascript — fazo, Mar 04 '11 at 10:03

score 5 · Answer 1 · answered Mar 04 '11 at 10:02

5

It makes an anonymous function and executes it. You use it to prevent variables from poluting the global scope.

(function(){
  var test = "Hello";
})();

alert(test); //test will be undefined here

answered Mar 04 '11 at 10:02

Decko

score 4 · Accepted Answer · answered Mar 04 '11 at 10:01

4

The function is immediately executed after parsing it.

answered Mar 04 '11 at 10:01

TurBas

ok, what is the reason to put it in a function body then, rather than just writeing its code within the script tags? – Nickolodeon Apr 12 '12 at 07:27

score 0 · Answer 3 · answered Mar 04 '11 at 10:04

0

Well, you use a function expression as a closure which gets executed immediately and 'this code at here' will not pollute global namespace.

answered Mar 04 '11 at 10:04

Torsten Becker

3 Answers3