Self-executing functions for JavaScript

Self-executing function is actually "function immediately", it has four features: improve performance, facilitate compression, avoid conflict, dependency loading;

1. Reduce Scope Lookup

JS Code:

1 // Anonymous function that has three arguments   2 function (window, document, $) {  3   4   //  can now reference the window, document, and JQuery objects in a local scope  5   6//

In other words, the scope is placed in the scope of the self-executing function, and the JavaScript interpreter is now looking for the scope of the function itself, followed by the global lookup.

Self-executing functions for JavaScript