Frankly, your sentence doesn't make much sense. HTTP is a way of sending text and data, so UDP would never be used. The data needs to arrive, be in order, and be correct (exactly what TCP does). Also, the fact that a new HTTP protocol is being used has no effect on javascript, since the protocol is essentially abstracted away.

As for your real question, when will javascript have UDP socket support, that is an interesting question. The feature would definitely be handy for multiplayer games and video/audio streaming. In light of this, I'm sure something will come down the pipe eventually. There could be security worries though, for example it could be used to build a webpage that performs a DDoS (not that they can't be built already).

Can you elaborate on how UDP would benefit JS? Have you seen Google's TCP fast start proposal (from yesterday, I believe)?

PeerConnections (will soon) give you pseuedo-UDP-socket-like ability in JavaScript. That with Media Source APIs and device access, one can build a p2p skype clone exclusively in the browser.