Forms are such a common element on the Internet we tend to blunder through them without too much thought. However, if the web site has added a few nice touches that make the process easier, it tends to speed up the process and reduce any frustration in finding our preferred username (i.e. try getting your name under Hotmail!).

There’s two types of validation:

1. Simple, server-independent validation, i.e. checking email address are the right format, password and confirm password matches, etc.
2. Server-based validation, with can be delivered with a page refresh, or live (as this tutorial will explain), i.e. for checking whether a username is taken.