JQuery_ Novice to Ninja - Earle Castledine [6]
jQuery UI
jQuery has already been used to make some impressive widgets and effects, some of which were useful enough to justify inclusion in the core jQuery library itself. However, the jQuery team wisely decided that in order to keep the core library focused, they’d separate out higher-level constructs and package them into a neat library that sits on top of jQuery.
That library is called jQuery User Interface (generally abbreviated to just jQuery UI), and it comprises a menagerie of useful effects and advanced widgets that are accessible and highly customizable through the use of themes. Some of these features are illustrated in Figure 1.1.
Figure 1.1. A few jQuery UI widgets
Accordions, sliders, dialog boxes, date pickers, and more—all ready to be used right now! You could spend a bunch of time creating them yourself in jQuery (as these have been) but the jQuery UI controls are configurable and sophisticated enough that your time would be better spent elsewhere—namely implementing your unique project requirements rather than ensuring your custom date picker appears correctly across different browsers!
We’ll certainly be using a bunch of jQuery UI functionality as we progress through the book. We’ll even integrate some of the funky themes available, and learn how to create our own themes using the jQuery UI ThemeRoller tool.
Plugins
The jQuery team has taken great care in making the jQuery library extensible. By including only a core set of features while providing a framework for extending the library, they’ve made it easy to create plugins that you can reuse in all your jQuery projects, as well as share with other developers. A lot of fairly common functionality has been omitted from the jQuery core library, and relegated to the realm of the plugin. Don’t worry, this is a feature, not a flaw. Any additional required functionality can be included easily on a page-by-page basis to keep bandwidth and code bloat to a minimum.
Thankfully, a lot of people have taken advantage of jQuery’s extensibility, so there are already hundreds of excellent, downloadable plugins available from the jQuery plugin repository, with new ones added all the time. A portion of this can be seen in Figure 1.2.
Figure 1.2. The jQuery plugin repository
Whenever you’re presented with a task or problem, it’s worth checking first to see if there’s a plugin that might suit your needs. That’s because almost any functionality you might require has likely already been turned into a plugin, and is available and ready for you to start using. Even if it turns out that you need to do some work yourself, the plugin repository is often the best place to steer you in the right direction.
Keeping Markup Clean
Separating script behavior from page presentation is best practice in the web development game—though it does present its share of challenges. jQuery makes it a cinch to completely rid your markup of inline scripting, thanks to its ability to easily hook elements on the page and attach code to them in a natural, CSS-like manner. jQuery lacks a mechanism for adding inline code, so this separation of concerns leads to leaner, cleaner, and more maintainable code. Hence, it’s easy to do things the right way, and almost impossible to do them the wrong way!
And jQuery isn’t limited to meddling with a page’s existing HTML—it can also add new page elements and document fragments via a collection of handy functions. There are functions to insert, append, and prepend new chunks of HTML anywhere on the page. You can even replace, remove, or clone existing elements—all functions that help