For the function (function($){})(), I've seen it with the word jQuery in it, why is that?

Question

For the function (function($){})(), I've seen it with the word jQuery in it, why is that?

I have read this page http://stackoverflow.com/questions/1925291/javascript-why-does-jquery-do-this-function-and-how-does-it-work but it didnt tell about an example like this:

(function($){})(jQuery);

What does that jquery in the parenthesis do? If the parenthesis by itself already self calls the function then why do we need that jQuery in there?

Answer 1

Is a simple function invocation, the jQuery object is sent as an argument to the anonymous function, e.g.:

(function (foo) {
  alert(foo); // alerts "hello"
})("hello");

It's a common pattern to define plugins, basically permits you to reference the jQuery object as $ in the scope of the anonymous function, even if jQuery is running in noConflict mode.