10 ILCS 5/17-1

and continued open until 7:00 p.m. of the same day, at which time the polls shall be closed; but if the judges shall not attend at the hour of six o'clock in the morning, or if it shall be necessary for the electors present to appoint judges to conduct the election, as herein prescribed, the polls may, in that case, be opened at any hour before the time for closing the same shall arrive, as the case may require.