click points in a picture to invoke some event so that woody form can be changed

[Christina <le...@hotmail.com>]

Maybe my question is silly because I am new to web development.

I have a picture.  I want to position serveral handred points onto this picture, 
whenever users click one of those points, the responding piont's color is changed, some event like a "change"  is invoked so that  woody form in this page can be changed accordingly.
But now I totally have no idea how to achieve that 
1. how to position so many points on a picture and change the responding point upon click? of course each point has an id
2. how to produce a "change" event for clicking on any pionts?
3. and what components of cocoon can help?
 
Thank you for your advice!!
Thanks a lot!!!!