Customizing and optimizing selectors

The many techniques we've seen give us a tool chest that can be used to find any page element we want to work with. The story doesn't end here, though; there is much to learn about performing our element-finding tasks efficiently. This efficiency can take the form of both code that is easier to write and read, and code that executes more quickly inside the web browser.

Writing a custom selector plugin

One way to improve legibility is to encapsulate code snippets in reusable components. We do this all the time by creating functions. In Chapter 8, we expanded on this idea by crafting jQuery plugins that added methods to jQuery objects. This isn't the only way plugins can help us reuse code, though. Plugins can also provide additional selector expressions, such as the :paused selector that Cycle gave us in Chapter 7.

The easiest type of selector expression to add is a pseudo-class; these are the expressions that start with a colon, such as :checked or :nth...