Wow, that's so cool! I played around with making HTAs as a kid and never thought those could be that powerful. (I quickly moved on to topics more exciting to a teenage hacker, like making WinForms apps with some PHP RAD IDE.)
Wondering what would it take to port mshta (with all the ActiveX goodies) to other platforms. Maybe it's a little bit late for that, but sounds like it might be a fun project to me.
You're brave, putting "ActiveX" and "fun" in the same sentence.
Wine Gecko supports ActiveX, supposedly, so if someone implements all the common ActiveX components, that could be a cross-platform method of running HTAs outside of Windows.
That said, I'm afraid the Electron API is the closest thing we have to a cross platform HTML application these days. On Manjaro, several packages are already implemented by installing Electron next to the application specific code, so that would be the closest thing to a modern HTA alternative that I know of.
PWAs work fine if you don't need integration with the system itself other than file prompts, for chat apps for example. They're not really alternatives to HTAs to be honest.
It should be noted that HTAs are a common way to infect computers (because they're executables that aren't usually recognised as such) and they're disabled in many security conscious environments.
To be honest, in my ideal world, mshta, Electron and the like would be discontinued and, instead, there'd be a cross-desktop-platform HTML/CSS/JS app-runtime (_not a browser!_). This runtime should support a sensible, large subset of modern Web APIs plus a set of cross-OS and OS-specific APIs so it's easy to work with for developers. To be easy to use for users, it should be installed by default on all major consumer-facing OSes. So yeah, it's probably not gonna happen anytime soon...
Wondering what would it take to port mshta (with all the ActiveX goodies) to other platforms. Maybe it's a little bit late for that, but sounds like it might be a fun project to me.