Why write code Jquery like this

Question

Why write code Jquery like this?

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

Answer 1

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

This type of Module pattern is very used out there. It invokes itself passing a reference to jQuery providing faster access to the variable, as it now lives in the scope of the function, and it also prevents global pollution.

The second one:

$(function () {
    .......
});

Runs the anonymous function once the DOM is loaded, that you make sure that everything is ready before executing any code.