(1) The right to enact ordinances for any city of the metropolitan class is hereby granted to the qualified electors of such city, but such grant is made upon the following conditions and in addition to the right granted to the city council to legislate as provided in this section.

(2)(a) Whenever qualified electors of any city of the metropolitan class equal in number to fifteen percent of the vote cast at the last preceding city election petition the city council to enact a proposed ordinance, it shall be the duty of the city council to either enact such ordinance without amendment within thirty days or submit such ordinance to a vote of the people at the next election held within such city regardless of whether such election be a city, county, or state election.

(b) Whenever such proposed ordinance is petitioned for by qualified electors equal in number to twenty-five percent of the votes cast at the last preceding city election and such petition requests that a special election be called to submit the proposed ordinance to a vote of the people in the event that the city council shall fail to enact such ordinance, the city council shall either enact such ordinance without amendment within thirty days or submit such ordinance to a vote of the people at a special election called by the city council for that purpose. The date of such election shall not be less than fifty days nor more than seventy days after the filing of the petition for the proposed ordinance.

(3) The petition provided for in this section shall be in the general form and as to signatures and verification as provided in section 14-212 and shall be filed with the city clerk. Upon the filing of a petition, the city clerk and the county clerk or election commissioner of the county in which the city is located may by mutual agreement provide that the county clerk or election commissioner shall ascertain whether the petition is signed by the requisite number of voters. When the verifying official has ascertained the percent of the voters signing such petition, such official shall transmit his or her findings, together with such petition, to the city council.

(4) In the event the city council shall fail to enact such ordinance, the city council shall submit such ordinance to a vote of the people of such city as provided in this section. The mayor shall notify the electors of such election at least fifteen days prior to such election, and the city council shall cause to have published a notice of the election and a copy of such proposed ordinance once in each of the daily legal newspapers in or of general circulation in the city, or, if there is no such newspaper, then once in each weekly legal newspaper in or of general circulation in such city. Such publication shall be not more than twenty nor less than five days prior to such election.

(5) All proposed ordinances shall have a title which shall state in a general way the purpose and intent of such ordinance.

(6) The ballots used when voting upon such proposed ordinance shall contain the following: For the ordinance (set forth the title thereof) and Against the ordinance (set forth the title thereof).

(7) If a majority of the electors voting on the proposed ordinance shall vote in favor of the question such ordinance shall become a valid and binding ordinance of the city. An ordinance adopted as provided in this section shall not be altered or modified by the city council within one year after such adoption.

(8) Any number of proposed ordinances may be voted upon at the same election in accordance with the provisions of this section except that the same measure, either in form or essential substance, shall not be submitted more often than once every two years.