how to change color of part of image(like periodic table) on

[admin]

I need to change the color of part of a image on click. Like in Chemical periodic table, if you click on one box, I want to change the color of that box plus on double click want to change the same back to normal.
like in this page:
chemical Periodic table page (<!-- m --><a class="postlink" href="http://www.chemicool.com/">http://www.chemicool.com/</a><!-- m -->)
Any help will be appreciated.

Thanks,

Sandeep Makharia