Hi,

The event date can be fetched in this form:

$('#calendar').fullCalendar({
    events: [
        // events here
    ],
    editable: true,
    eventDrop: function(event, delta, revertFunc) {

        alert(event.title + " was dropped on " + event.start.format());

        if (!confirm("Are you sure about this change?")) {
            revertFunc();
        }

    }
});

When the event is drop in the specific date, you can get it with event object event.start.format()

Hopefully this will help you.