Plugins need not be limited to providing additional jQuery methods. They can extend the library in many ways, and even alter the functionality of existing features.
Plugins can change the way other parts of the jQuery library operate. Some offer new animation easing styles, for instance, or trigger additional jQuery events in response to user actions. The Cycle plugin offers such an enhancement by adding a new custom selector.
Plugins that add custom selector expressions increase the capabilities of jQuery's built-in selector engine, so that we can find elements on the page in new ways. Cycle adds a custom selector of this kind, which gives us an opportunity to explore this capability.
Cycle's slideshows can be paused and resumed by calling .cycle('pause') and .cycle('resume') respectively. We can easily add buttons that control the slideshow, as shown in the following code:
$(document).ready(function() {
var $books = $('#books');
var $controls = $...