I’ve worked a lot with jquery (a popular javascript library) over the past few years, and I recently added a nice bit of ajax functionality to a site.

The function is a simple “type-ahead” lookup for a searchbox – just start typing, and results will show up, filtering out as you go.  Here’s the site:

philly.thedrinknation.com

The search box is in the upper right under the social icons.  Note this site also uses ajax on this page:

philly.thedrinknation.com/bars/search

These features are becoming more commonplace, and more expected on websites.  Almost all browsers can support them now, even mobile browsers, so there’s no reason not to use them anymore.