No, not even in late 90's. Emulators for GB/GBA (sometimes MSX/ZX/C64...) and PSX/N64 did far, far more than JS. When you could play for free games for the N64 (which weighted just a few MB's, good enough to get them from cybercafés in CD-ROM and play THPS2 at home), you have to be good to at least understand what the graphics mode did to emulators, the filters, the audio quality on CPU usage, and sometimes even hex-editing some ROM headers to enforce compatibility with some emulators.

And, a bit later, in early 00's, compiling them for GNU/Linux for performance and patching some of them to understand odd bootleg NES cartridge mappers.