ajax dropdown with clientside filtering capability

Can any one provide me an idea about any ajax control which has following capabilities:

1. User should able to type to get auto-suggestions

2. Dropdown should only display the values starting with the keyed-in ch开发者_JAVA技巧aracters.

3. Most importantly there should be only one postback to fetch all the data to client side on the first key-in and then should filter the list values based on rest of the keys.

Any ideas in this regard greatly appreciated..

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Check out this demo of the Autocomplete control in the jQuery UI library: http://jqueryui.com/demos/autocomplete/ The demo demonstrates all the features you need and provides source for it all.