Well, you couldn't use an include file unless you wanted to reload. Inclusion is server-side, and the javascript is client-side.
You could, however, make a bunch of DIVs with the information, and hide every one but the one you are looking at. (It could be named by ID or after the person, for an example.)
If you want to use inclusion, you'll have to put everything in a form, and have the onChange submit the form. This ensures you do not lose any data, but you will have to compensate for the fact that it can be submitted two ways (submit button, or onChange).
Hope this helps.