Rails 2.3.8, jQuery - How do I redirect a checkbox check action to an action in the Controller using Ajax/jQuery?

This is an urgent question. I have a scenario where, upon clicking on a checkbox in an overlay with empty form fields, the form fields fill up automatically based on a Controller action. For this, I need to redirect to a Controller's method upon immediate checking of the checkbox in the overlay.

Ex: Overlay has an empty form. Checkbox: Copy details from existing page into the overlay Upon checking the mentioned checkbox, my empty form overlay has to be filled in with form details from the underlying page. So the checkbox check should lead to an action in the Controller and fill in the form in the overlay via Ajax