Win 7 , get fallback xhr-streaming / xhr-polling / eventsource protocol after first websocket connection

[cuon...@dirox.net]

I logged the protocol in node server when client connected.
I test on Win 7 laptop, open web application then connect sockjs to node server.
First , I get logged protocol is "Websocket". But after that it get new connection but protocol is xhr-streaming, and sometimes fallback to xhr-polling  / eventsource / htmlfile
I check network tab in web application.
I get the same log
websocket
then
xhr-streaming
...