This wasn’t obvious to me, so I am posting this in case other authors are not aware of this either:
Or take a look the website: Adrift 4 demo using Parchment on itch.io by kenped
I found a quite simple way to make online play available on itch.io for all formats Parchment can handle. So besides Glulxe and Z-code, there is a simple way to make TADS 2, TADS 3, Hugo and Adrift 4 games playable online at itch.io by utilizing Parchment. Well, I have only tested it for ADRIFT 4 games but I would assume it works for the other formats as well.
I simply upload an html-file with the following code:
<!DOCTYPE html>
<html>
<body>
<head>
<center>
<meta http-equiv="Refresh" content="0; url='https://iplayif.com/?story=http://www.adrift.co/files/games/DenkAdrift4demo_1.taf'" />
</center>
</body>
</html>
It is necessary that your game is available somewhere on the net unzipped unless it is in the IF Archive, then it can work zipped as well.
This works well on itch.io. It would be interesting to ask the textadventures.co.uk-team if this would be acceptable on their site too? (Perhaps @The_Pixie can answer that?)
I don’t see their site getting flooded with z-code games so I don’t think allowing this approach would change that for other formats either. E.g. being able to play The Mulldoon Legacy or other great non-Inform games there would be great (assuming the authors allow it).