How to pass form value through URL?

I have a page set up so that pressing the submit on a form will execute a certain page. For certain reasons I also have a URL HREF link that performs a different function. I need to get the value of a radio button group (all with the same name) and pass that value through the URL if it is pressed. So if someone clicks on the second radio button in the list which has a value of 2, I need to somehow set that to a variable to pass through a URL link. Each time the user changes the radio button I need to dynamically change the variable too.

Is there any way to do this?