Bracket System - Need Help!

[Lamez]

I am making a bracket based website for my dad, for the NCAA.

 

Anyways, I have never used ajax, and I told I was making a bracket based website so you could get a better understanding, of what I am asking for help on.

 

I need some drop down list that will update the next one based on what was just selected, and add the selections to a database.

 

Example:

Round 1

Team A *User selected*

Team B

 

Round 2

Team A

Team C *User Selected*

 

Round 3

Team C

Team D

and so on...

 

-Thanks!