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

Question

I get a *.js file code similar like:

(function(a){ 

   a("#div_element").removeClass("show message");
 
   ....

})(jQuery);

I'm trying to understand:

What is (function(a){...})(jQuery); ?
How to use it?
What is a here? Because I seen normal code looks like:

$("#div_element").removeClass("show message");

possible duplicate of What does this mean? (function (x,y)){...}){a,b); in JavaScript — Guffa
– Guffa, Commented May 24, 2011 at 5:44
Other similar questions: stackoverflow.com/questions/4806150/…, stackoverflow.com/questions/5192227/…, stackoverflow.com/questions/4043647/…, stackoverflow.com/questions/440739/… — Guffa
– Guffa, Commented May 24, 2011 at 5:47

Community · Accepted Answer · 2017-05-23 10:24:12Z

2

function( a ){ /* … */ } is an anonymous function that is directly called with jQuery as parameter. So a inside the anonymous function is the same as jQuery

From jQuery website

Example: Reverts the $ alias and then creates and executes a function to provide the $ as a jQuery alias inside the functions scope. Inside the function the original $ object is not available. This works well for most plugins that don't rely on any other library.

jQuery.noConflict();
(function($) { 
  $(function() {
    // more code using $ as alias to jQuery
  });
})(jQuery);
// other code using $ as an alias to the other library

read this post also:

What does (function( $ ){...})( jQuery ); do/mean?

edited May 23, 2017 at 10:24

CommunityBot

11 silver badge

answered May 24, 2011 at 5:37

xkeshav

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Comments

David Titarenco · Accepted Answer · 2011-05-24 05:52:07Z

1

Maybe it's easier to understand the mechanism by thinking of it this way:

(function( blah ) {
    blah("hello");
}) ( alert );

Note how blah becomes a proxy for alert. This is just a fancy way of not polluting the global namespace (a lot of libraries use the $ as a global variable).

answered May 24, 2011 at 5:52

David Titarenco

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