I've recently been playing with the Gamepad API and implementing it in Rawkets (gamepad stuff isn't online yet, sorry!). Up until a few days ago this was a Firefox-only feature but I'm glad to say that builds of Chrome are now out with gamepad support. Here is a quick video of Rawkets with the Gamepad API working in Firefox and Chrome.
I'm looking forward to this functionality maturing and getting supported by the other browsers. For now you can play with this today in experimental Nightly builds of Firefox or download the Chrome Dev build for Windows support, or Chrome Canary for Mac support (Linux coming soon).