js-ipfs, the Javascript implementation of IPFS, has made a lot of progress in the past 6 months. It's still early but totally usable.
We've been working on go-ipfs and js-ipfs interop so that browser nodes can talk to "native" nodes. It's not fully ready yet but soon. This will open a lot of doors for a more advanced network and applications using IPFS.
See https://github.com/ipfs/js-ipfs.
As for your question re. ipfs.io using js-ipfs, the answers is no, it doesn't use js-ipfs implementation yet.