Any idea how this auto complete works?

I am curious as to how the autocomplete functionality works on the following site:

As soon as you type a letter, it instantly displays a drop down list of possible matches.

I know this site has probably cost millions to develop but wondered if this functionality is something I can replicate on my site?

Thanks

Paul

If you think that’s clever, visit www.ft.com, click the quotes radio button next to the search box and start entering either a company name OR its stock market code eg rolls or rr and watch Rolls-Royce appear, or vod for vodafone, with several different stock exchanges to choose from.

Google does it too. You can do it with ajax.

Hey thanks for the replies - seems so instantaneous I can hardly believe it is coming from a database query. Guess FT and Google have pretty amazing set ups though.

Thanks for the link to the ajax tutorial - will give it a peek and see if my shared hosting is up to any autocomplete antics

Wow, that is really cool, but I think that it is over my head to set it up myself. Guess I would have to get my programmer to do it for me, but that would cost $$$. I think my users are just going to miss out.