When such petition demands the enactment of an ordinance or other legal act other than the grant, extension, or renewal of a franchise, the chief executive officer shall present the same to the legislative body of such corporation at its next meeting, and unless the said petition shall be granted more than thirty days before the next election at which any city officers are to be elected, the chief executive officer shall submit the said ordinance or act so petitioned for, to the qualified electors at said election; and if a majority of said electors voting thereon shall vote for the same, it shall thereupon become in full force and effect.