I am using the winpc. I don't know some case in machine.
When people closing the tab in safari, the server will not receive the client's ping data afater 3-4 minutes by default, maybe it is a hidden bug :))
In some browsers , such as firefox, safari, chrome, the
socket.io client will be choose the websocket to connect the server instead of flash.
With some test case, the pc safari 、ipod touch safari use the websocket at first.