(a) A person may not be registered as a voter except by affidavit of registration. The affidavit shall be mailed or delivered to the county elections official and shall set forth all of the facts required to be shown by this chapter. A properly executed registration shall be deemed effective upon receipt of the affidavit by the county elections official if received on or before the 15th day prior to an election to be held in the registrant's precinct. A properly executed registration shall also be deemed effective upon receipt of the affidavit by the county elections official if any of the following apply: (1) The affidavit is postmarked on or before the 15th day prior to the election and received by mail by the county elections official. (2) The affidavit is submitted to the Department of Motor Vehicles or accepted by any other public agency designated as a voter registration agency pursuant to the National Voter Registration Act of 1993 (42 U.S.C. Sec. 1973gg) on or before the 15th day prior to the election. (3) The affidavit is delivered to the county elections official by means other than those described in paragraphs (1) or (2) on or before the 15th day prior to the election. (b) For purposes of verifying signatures on a recall, initiative, or referendum petition or signatures on a nomination paper or any other election petition or election paper, a properly executed affidavit of registration shall be deemed effective for verification purposes if both (a) the affidavit is signed on the same date or a date prior to the signing of the petition or paper, and (b) the affidavit is received by the county elections official on or before the date on which the petition or paper is filed. (c) Notwithstanding any other provision of law to the contrary, the affidavit of registration required under this chapter may not be taken under sworn oath, but the content of the affidavit shall be certified as to its truthfulness and correctness, under penalty of perjury, by the signature of the affiant.