HTML5 games are not nearly as endangered as Flash games, and are in fact often cited as replacing the Flash medium. However, they still pose a risk of disappearing at some point in time, and therefore should be considered for curation just like other web game formats.
The following page is a tutorial on how to curate HTML5 games to add to Flashpoint.
Before You Start
This tutorial will assume you've read the standard Curation Tutorial, which is highly recommended to go through. Try curating a Flash game before moving on to HTML5.
Identifying HTML5 Games
If a web game doesn't ask to enable Adobe Flash Player and there's no sign or mention of any of the other Platforms, it is very likely an HTML5 game.
To confirm this, press F12 to open the Developer Tools of your browser and click the Network tab. Look for a .html file, likely under the title "index.html". Copy the file's link and go to it. If it plays an unobstructed version of the game, you've found the source of your Launch Command.
Make sure to always use http:// instead of https:// to make sure Flashpoint grabs files from the fake Internet instead of the real one!
Grabbing The Game From The Internet
Saving .html pages is really easy, simply right click and "save as" (or use Ctrl-S). Make sure you're saving it as a basic webpage and not a complete one, as there's a bunch of needless junk that can come along with it.
Moving The Game Into Flashpoint
It's good practice to name content folders directly after the URL of your file to prevent softlocking. In Flashpoint Core's Server/htdocs folder, create a series of folders named after the URL leading to your .html file.
In Flashpoint Core itself, create a new game and fill it out with as much information as you can, including the Launch Command you found earlier. The Platform should be "HTML5", and the Application Path should be "FPSoftware\Basilisk-Portable\Basilisk-Portable.exe". The Basilisk browser is used in Flashpoint to run HTML5 games.
Test your game. Almost all HTML5 games will certainly be multi-asset, so don't be surprised if the game doesn't work at first.
Check the Flashpoint Redirector for a series of URLs of the assets for your game, assuming your content folder is based directly off of the source URL. Select Tools/Copy all 404 Not Found URLs. From here, you can either use cURLs Downloader to batch download the assets (see here for more information) or manually download and insert the files into your content folder.
Test the game repeatedly to check for additional assets the Redirector calls for. Once you're sure you've downloaded all the assets, test the game again to make sure everything works properly as it does online.
Alternatively, if you don't want to jump back and forth between getting 404s and downloading them, you can use MAD4FP. Please be careful when using this, as it downloads everything that still exists, meaning you can get a lot of unnecessary files. Also, if you leave it on when trying to use normal Flashpoint it will break the program.
Wrapping It Up
Follow the proper Curation Format, including all content folders requested by the Redirector.
Pack everything into a single .zip file and submit it to the #other-game-curations channel of the Flashpoint Discord. Use the HTML5 emoji when submitting.