Now to mark an episode as watched you got to click on the episode to go to the episode page and choose "watched" from the dropdown list. How about adding a little watched/unwatched button (on/off) in every episode box on the calendar page? That way you would be able to mark an episode as "watched" without leaving the calendar page.
This is possible in the weekly calendar (see https://www.tvmaze.com/features/tv-episode-calendar). We haven't added it to the monthly calendar because it'd be too cluttered in the small space available there.
If you're fine with an unofficial version for the monthly calendar, I have one here:
https://openuserjs.org/scripts/gazza911/Mark_From_Calendar
There's some variables will change if you feel like changing them (there's comments to explain each one)
(Instructions to install are on the link)
Hi Teros,
Feature added. You can read more about it in this blog.
(Or you can continue to use gazza's script.)