65 ILCS 5/3.1-20-45
A city incorporated under this Code that elects municipal officers at nonpartisan primary and general elections shall conduct the elections as provided in the Election Code, except that no office for which nomination is uncontested shall be included on the primary ballot and no primary shall be held for that office. For the purposes of this Section, an office is uncontested when not more than 4 persons to be nominated for each office have timely filed valid nominating papers seeking nomination for the election to that office.
Notwithstanding any other provision of law , when a person (i) who has not timely filed valid nomination papers and (ii) who intends to become a write-in candidate for nomination for any office for which nomination is uncontested files a written statement or notice of that intent with the proper election official with whom the nomination papers for that office are filed, no primary ballot shall be printed. Where no primary is held, a person intending to become a write-in candidate at the general primary election shall refile a declaration of intent to be a write-in candidate for the general election with the appropriate election authority or authorities .
If there is a primary election, then candidates shall be placed on the ballot for the next succeeding general municipal election in the following manner:
The name of a write-in candidate may not be placed on the ballot for the next succeeding general municipal election unless he or she receives a number of votes in the primary election that equals or exceeds the number of signatures required on a petition for nomination for that office or that exceeds the number of votes received by at least one of the candidates whose names were printed on the primary ballot for nomination for or election to the same office.
65 ILCS 5/3.1-20-45