dynamically associate radio buttons with droplists

[Leo Brugud]

Hi Folks,

Not being very familiar with python, nor with cgi/http,  I intend to
have 3 of buttons in a webpage, each of them is associate with a file
(so I have 3 files, too)

What I would like to have is, when users choose a button, the droplist
update automatically to load the contents of the associated file.

Can someone educate me the approach of this?

Thanks