I don’t think it is the plugins faults. It looks like there is an issue with enscripten in version 4.13+ that won’t let HTML5 compile with third party plugins. If you got a chance you could try a couple and let me know if you got any to pass. Just make a project, turn on a plugin and try to build for HTML5.
Sadly I don’t have the time for that currently.
Sounds like you analyzed the logs already and search on google for it, so I can’t really add help here, since I’m not familiar with HTML5.
Sending information to a website should be done with these though.
I assume you are not good at C++?
Otherwise you could try to add the functionality by yourself. So you would simply get the Plugin Source and add it to your project directly.
But if you can’t use C++, then it might get a bit tricky if not impossible.
You can check the remaining console commands, but despite that, I don’t know of any node that pushes data to a website.
I also don’t know if you can suppress the Page opening of “Launch URL”, but I would guess you can’t.