jQuery is a fantastic library for designing and developing user interactions quickly. Whether it’s an image gallery or form, content-revealing animation or an explosion effect, the library provides the core building-blocks to allow you to rapidly prototype and deliver a unique user interface with the minimum of code and effort.
This presents an interesting question, however. Just because you can roll your own solution to any given problem, does that mean you should? Of course not! There’s absolutely no need to reinvent the wheel every time you want to create a bit of common functionality; use plugins to instantly add a behaviour. Doing so will save you even more time and effort! Here’s a nice new list.