The Mayor shall receive an annual salary as set from time to time by an ordinance passed by the Council in the regular course of business; provided, however, that no change shall be made in the salary for any Mayor during the term for which he was elected. The ordinance making any change in the salary paid to the Mayor, either by way of increase or decrease, shall be finally ordained prior to the municipal election to elect the next succeeding Mayor and shall take effect only as to the next succeeding Mayor.