如何检查是否单击已选择的单选按钮

I have several rows of twin radio buttons that are generated via a loop in ruby on rails. For each row, one of the button is already selected, how do i detect if the user accidentally click on a radio button that's already selected? Keep in mind these buttons all have generated ids so I can just look for a specific id. Can someone show me how to do this via ruby on rails or javascript? Thanks.I have several rows of twin radio buttons that