TextExt is a plugin to help you achieve autocomplete with jQuery. But this is not the only thing TextExt can do! This jQuery plugin was design to easily turn a standard HTML text input into a wide range of modern, tailored to your needs input field.
Besides autocomplete with jQuery, it includes a wide number of plugins like tags, filter, ajax, as well as a few which are purely aesthetic like Focus. TextExt is very well documented, regularly improved and provides a list of examples for you to start with.