Jquery Undo - preventdefault
===

I have a some textboxes and a drop down. 
If the user does not have permission to modify them, I like to 
show a message and undo what they selected in teh case of a drop down 
or to undo what they types - in the case of a text box.

I tried the following for a drop down but did not work:

        $('#ReasonDropDown').change(function () {

            if (permission == "False") {
                alert("You do not have permssion to make to modify this field.");
                event.preventDefault(); 
                return false;
            }
        });

It simply did not undo what I had selected. 