Professional Ajax, 2nd Edition

8.4. Creating an Autosuggest Textbox

The best way to learn about any new programming concept is to put it into a practical example. Google Suggest (located at www.google.com/webhp?complete=1) is a very simple Ajax application that many programmers have spent time dissecting, analyzing, and re-creating. If you haven't yet taken a look at the live application, please do so now; it will greatly aid in your understanding of the following example.

Functionality such as this, suggesting to the user values to type in, has been around in desktop applications for some time now. Google Suggest brought the idea to the Web and generated a lot of excitement while doing it. As mentioned earlier in the book, Google Suggest was one of the very early Ajax applications that got developers excited about the concept. It seems fitting to attempt to emulate the behavior of Google Suggest to help others understand Ajax.

The example built in this section aids in the selection of states or provinces in a personal information form. For sites that deal with international customers, it is often vital to include the state or province along with the country. However, it's not optimal to load every state and province in the entire world into a drop-down box for the user to select from. It's much easier to let the user start typing and then retrieve only those results that would make the most sense. Autosuggest functionality is perfect for this use case.

8.4.1. Functionality Overview

Before building anything, ...