The ballots used when voting upon ordinances proposed under the initiative or under the referendum, shall set forth the title of the proposed ordinance, and shall state its general nature, and shall contain the words, “For the ordinance,” and “Against the ordinance.” If a majority of the votes cast on any ordinance initiated as herein provided, by the electorate of the city, shall be in favor of said ordinance, it shall, if not already in effect, go into effect as a valid ordinance of the city, one day after the official canvass and declaration of the result, unless a later date is provided by the terms of said initiative measure; otherwise such ordinance shall be rejected.