About $ (function () {}), and (function ($) {...}) (jQuery) $ (function () {}); The code used to hold the DOM object, the DOM object already exists when executing code. cannot be used to store code that develops plug-ins, because jquery objects are not passed, and external methods (functions) cannot be called by Jquery.method.
(function () {}) (JQuery), which is used to store the code that develops the plug-in, and the DOM does not necessarily exist when executing the code, so be careful with the code that automatically executes DOM operations directly. Simple to understand is (function ($) {...}) (jQuery) defines a number of functions that need to be pre-defined
$ (function () {}) is used to run \ Execute those preprint-defined functions after the DOM loading is complete. First, the Ready () method is executed after the DOM has been loaded. $ (document). Ready (function () {}), abbreviated as: $ (function () {}) II, to define a number of functions that need to be pre-defined (function (ARG) {}) (param) to define an anonymous function with the parameter arg. and call this anonymous function param as a parameter, which is called the function is actually equal to
var fn = function ($) {...};
fn (jQuery); The reason for using only $ in formal parameters is to not conflict with other libraries, so the argument is actually understandable with jquery, but it is important to note that FN does not exist.
The function FN is defined directly and then runs. "Compression" looks like this.
(function ($) {...}) (JQuery)
(function () {}) (JQuery)
