Confirmation is necessary when you want to remind, warn, or make a user especially aware of the importance of a change or choice that they are about to make. Confirmation can happen in industrial design, such as when you have to confirm your intention to arm a device by lifting a protective flap over a trigger, but we encounter it far more often in software, where we are asked if we really want to perform an action. A very simple implementation of confirmation occurs on websites with the javascript alert function.