So what browser API does the PeerJS use to exchange data with something other than a server, particularly another browser?
Is this it? https://tools.ietf.org/html/draft-jesup-rtcweb-data-protocol...
If so, you still need wifi for the connection between them, The cool thing about PeerJS is that the data goes directly between the computers (A <--> B) without a server in between (A <--> S <--> B).
It's the only one I've seen that abides to the bittorrent spec (where possible). BEP 9 and 10 support incoming.
(Demo's broken, need to push a fix :()
Also note that currently DataChannels do not support reliable transfer and have a small MTU, so sending enormous files does not yet work. With PeerJS you can send smaller files, but larger ones will take an unreasonable amount of time.
Your browser version: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.31 (KHTML, like Gecko) Chrome/26.0.1410.43 Safari/537.31
Currently Google Chrome 26.0.1403.0 or above is required.