Weird JavaScript Syntax __java

A few days ago a colleague asked me how the following JavaScript code understood:

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

In fact, it is relatively simple to understand several concepts:

1, (), in JavaScript () indicates the execution of a method, such as:

function X () {

Alert ("xxx");

}

var a = x; No call, A is a function

var a = x (); The function is called, and the value of a is the result of the call: undefined

2, jquery is a jquery object, which means that when calling a function, passing in a parameter is a jquery object.

There's nothing to talk about here.

3, (function ($) {}) This is an anonymous function, the formal parameter is $, parentheses are necessary.

This is understood, the upper-style equivalent

var f = function ($) {};

f (jQuery);

Now look at, that is not simple nor strange ...