Problem with datagrid.....

Hello All...

I am having a problem with accesing the template columns of the
datagrid.

I have 2 template columns..One with 3 Radiobuttons and second column
is a dropdownlist control.
The Three radiobuttons are Yes, No and DontKnow. If i click Yes, then
corresponding Dropdownlist should be visible and if i click no then
dropdownlist should become invisible.

This should be done without reloading the page and should be done with javascript.

Please help me...or gimme an idea how to work on.....or in which way to work on..

Thanks,
Swetha.