CSS selectors

The jQuery library supports nearly all the selectors included in CSS specifications 1 through 3, as outlined on the World Wide Web Consortium's site: http://www.w3.org/Style/CSS/specs. This support allows developers to enhance their websites without worrying about which browsers might not understand more advanced selectors, as long as the browsers have JavaScript enabled.

Tip

Progressive Enhancement

Responsible jQuery developers should always apply the concepts of progressive enhancement and graceful degradation to their code, ensuring that a page will render as accurately, even if not as beautifully, with JavaScript disabled as it does with JavaScript turned on. We will continue to explore these concepts throughout the book. More information on progressive enhancement can be found at http://en.wikipedia.org/wiki/Progressive_enhancement.

To begin learning how jQuery works with CSS selectors, we'll use a structure that appears on many websites, often for navigation – the nested...