Just examples for wayback search syntax, no JS:
Nearest archive around a target date:
https://web.archive.org/web/201809/https://www.example.com/xyz
LIST of files starting with a cropped URL:
http://web.archive.org/cdx/search/cdx?url=https://www.example.com/xyz*&filter=statuscode:200&fl=timestamp,urlkey,statuscode,length,mimetype,statuscode,original&collapse=digest&limit=5
Forum:
Off-Topic