In order to prevent that parcels are not correctly sent into our network, a match between zipcode and city (filled in by the consumer) are made before the iFrame is loaded. 

If the zipcode and city do not completely correspond (e.g. Liège <> Liege), they are cleared before the iFrame is loaded and the consumer will need to reenter them again by using our combined dropdown list. This will always show him the correct combination, reducing the number of returning parcels due to wrong address input.