jQuery UI and jQuery Mobile are two additional libraries of the jQuery family. jQuery User Interface (UI) offers you a number of widgets that you can use in the user interface part of your site. My favorite ones are accordion and datepicker. Unlike jQuery itself, which is JavaScript only, jQuery UI also comes with a whole bunch of CSS files. This means that as soon as you use one of those widgets, they will have their own look and feel.

Not to worry, jQuery provides a cool tool called Themeroller. With this tool, you can generate a customized set of CSS files so that the colors and other look and feel features of the jQuery UI elements match those of your own stylesheets.

jQuery mobile is another jQuery based CSS/JavaScript extension that offers you user interface elements to create mobile first sites and applications. You can create web pages that will work on phones, tablets, and desktops. We will dedicate an entire chapter to mobile first, and then responsive...