What is the difference between (function(){/*.....*/})(); and (function($){/*.....*/})(jQuery);

Question

Is there difference between :

(function() {
     /*..........*/
})();

and :

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

Answer 1

Other people explained what the difference is, but not why you use the latter.

The $ variable is most often used by jQuery. If you have one script tag that loads jQuery and another that loads your code, it's perfectly fine. Now throw prototype.js into the mix. If you load prototype.js and then jQuery, $ will still be jQuery. Do it the other way around and now $ is prototype.js.

If you tried to use $ on such a page, you'd likely get errors or weird behavior.

There are many questions on StackOverflow about this problem. Plugins shouldn't assume much about the page they're loaded in, so they use this pattern defensively.