Dynamic stamp with Radio button.

I am creating a dynamic stamp on which there are four radio buttons. I know I have to execute JavaScript before inserting the stamp on any other PDF file. So, here is what I am attempting but my limited knowledge in JavaScript is not helping me.
On insertion of the stamp, I want a dialogue box to appear which asks for selection 1 or 2 or 3 or 4. Based on the number selected, the corresponding RadioButton is selected.
Can anyone help me do this?