The first letter typed is referenced to an array (which you place data into) and possible "solutions" are shown in a dynamic select box.
As the user continues to type, the possible "solutions" in the dynamic select box is refined.
The user can either use the mouse to make a selection or the arrow keys and the enter key.
Upon completion of either typing text which matches an option in the dynamic select box OR in choosing a select option the form is submitted.
This script is intended for selectable data which is fixed (such as a list of users in Active Directory, list of computer names, small tag cloud, etc), where you don't want to make dozens of calls to the server to extract the same type of data repeatedly with each keypress of each user.
NOTE: You can download the script from the main javascript page.