I don't think the script should save which pages YOU archived, but rather check for any archived version existing on archive.is.
yes i mean this, check if page is currently archived, if is usefull
Another nice feature would be an actual 1 clic archive button. Now you need to clic on the button, and then on archive on the new tab. This would allow to archive a lot of links fairly quickly.
open in new tab? mmmm sounds good, ok this is next improvement for version 1.1--- update ---
in my browser: Firefox, working good
video ->
https://imgur.com/Oja5h8K