What is this? (function(){ })() [duplicate]

Question

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Closed 8 years ago.

Possible Duplicates:
What does this JavaScript snippet mean?
Location of parenthesis for auto-executing anonymous JavaScript functions?

(function(){

    //something here...

})() <--//This part right here.

What exactly is this )()?
What if I change it to this ())?

(function(){

    //something here...

}()) <--//Like this

Answer 1

They are the same.

There has to be a parenthesis either around the function definition or around the function call to make it valid Javascript syntax, but it doesn't matter which you use.

To demonstrate what it does, using a named function it would be:

function something() {}

// parenthesis around the function reference:
(something)();

// parenthesis around the function call:
(something());

Answer 2

In JavaScript, function definition is a literal - which means, it's an expression with the value of the Function object.

If you put () right after it, you effectively call the function right after defining it.