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

Answer 1

That's simply an anonymous function. The () parens call the function immediately, instead of waiting for it to be called elsewhere.

Answer 2

It's an anonymous function that gets called immediately the () calls the function and there are ( and ) wrapping the whole thing.

( // arbitrary wrapping
(function() { // begin anon function

}) // end anon function
() // call the anon function
) // end arbitrary wrapping