radio button: event before checked prop change?

[jeckle]

I have a set of radio buttons in a form. Its checked state determines the state of a large number of other inputs later down the form. If the user goes back to it after moving down the form and changes its value, I need to clear much of the form, and the user will need to reenter many values. I would like to warn them that this is going to occur. Is there an event that fires before the checked prop is changed? Or should I throw the confirm on click and if they cancel, set the value back?To be clear, i know .click() fires after the checked property is changed. Is there an event that fires after the user clicks but before the checked property is changed?