4 or 5 Polling requests before WebSocket protocol is activated

I'm working with socket.io (the 1.0 version) and something weird happens. The server is very basic and without any message handling (which means only the connection signal is used and the disconnection one). Though it seems that the client sends multiple polling requests before trying to use websockets. For example here is a screenshot of the requests.THe requests

As you can see, it's really messy. There are some requests to my nodejs server, first some polling requests, then the websocket (switching protocol, indicated by the blue dot on the left) and then other requests for polling. Though I know it uses Websockets after that because there are no other polling requests once the Websocket is set. It makes my server to send some messages twice on the page load.

Does anyone ever experienced something like that ? Maybe it will just work fine. But I don't want to have this kind of behaviour. If you need additionnal information, just ask in the comments and I'll edit the main post.

Take a look at the last paragraph of New engine section. Socket.IO 1.0 first connects via XHR or JSONP, and then, if it's possible, switches transport to WebSocket on the fly. This explains why you have such messy network activity.