Ajax-for-codeigniter autocomplet restrict to list

[eluser]medium_kreation[/eluser]
hi,

I need to customise "Ajax for CodeIgniter" for my intranet application.
below are the 2 things i am stuck with.
1. Limit the inputs with the selection list. so that only valid data is inputed like HTML-FORM-Select-option. and if not it should punch an alert messege.

2. I need more than one column of data to be displayed in the list but only one of them should be submited.

i have seen a live example at script.aculo.us website but am unable to understand their code. can anyone help me to understand how to do it. the live demo of the example is here..

http://demo.script.aculo.us/ajax/autocom...customized

plz explain how to customise it for "Ajax For CodeIgniter" library.

thanks
kamal