Here is the example of auto complete functionality that is widely used in any web application. By using Jquery autocomple plugin you can easily implement this functionality.
First download this plugin ui.autocomplete.js from http://jquery.com/
There are different different function asociated with each and every event let say when you type any thing inside text field there is appropriate function for the same. Same as when any suggestion displayed for autocomplete there is a appropriate function for it..you can over ride that function as per your need.
Bewlow are the list of function associated with each and every event. You can over ride it
