Kayak provided one of the earliest examples of using AJAX to provide data filtering controls and live refinement or filtering of results. Their slider controls remain one of the best examples of how AJAX can be used to make filtering visual and intuitive. Sliders allow users to narrow down search criteria including flight duration, takeoff/landing time, and price.

1. Default filtering controls.
2. Search results page.
3. Search results after adjusting search filters.

http://kayak.com