Active Scripting is the technology you are thinking of, JScript and VBScript are just the frontends for it that are shipped with Windows. It's honestly a pretty cool idea on the surface (coming from someone that's never actually used it anyway), you could develop/obtain an implementation for your favourite language, access the same functionality exposed by ASP/Office/IE, and as script hosts they would be none the wiser as to what language was being used (of course, it gets less useful the more users you have to ask to install your plugin).

The closest modern thing that's like this I can think of is Godot and its GDExtension.