mxSelect updating a form field

[tomhwtt]

Hi,

I feel like I am missing something pretty basic here, I hope I don't
kick myself when I get the answer :)

I would like setup a drop down menu that updates another form field
using mxAjax.

I have tried both of the following examples with success:

http://www.indiankey.com/mxajax/examples/mxSelect2.cfm

http://www.indiankey.com/mxajax/examples/mxSelect1.cfm

However, I cannot seem to figure out how to choose an option in the
drop down menu and have it populate a text field below instead of a
<div> or <select>

Basically, I would like to have a list of items. When I choose the
item it calls the database and returns the weight of that item(or
another field).

Thank You for any insight you can provide

Tom