Using the dollar ($) alias in plugins

When we write jQuery plugins, we of course must assume that the jQuery library is loaded. We cannot assume, however, that the dollar ($) alias is available. Recall from Chapter 3, Handling Events, that the $.noConflict() method can relinquish control of this shortcut. To account for this, our plugins should always call jQuery methods using the full jQuery name or internally define $ themselves.

Especially in longer plugins, many developers find that the lack of the dollar ($) shortcut makes code more difficult to read. To combat this, the shortcut can be locally defined for the scope of the plugin by defining a function and immediately invoking it. This syntax for defining and invoking a function at once, often referred to as an Immediately Invoked Function Expression (IIFE), looks like this:

(function($) {
  // Code goes here
})(jQuery);

The wrapping function takes a single parameter to which we pass the global jQuery object. The parameter is named...