Yeah, you can use your 3DS as a controller on the Wii U version.

i mean online not locally

Then no. That wouldn't be possible due to different hardware and because the stages are most different.

Then do you know anyone here on juxt that could play smash 4 Wii U?

my 3ds isnt turning on btw... that's why im asking

I only play with some friends sometimes, but other than that, I'm not sure. Maybe you could make a post on that.

you can use the 3DS as a controller but u cant play online together cuz 3ds runs a different proccesser.