I am doing websocket between webview in iOS and Socketserver.
But I am unable to watch ping-pong that happens because javascript does not have any call back methods for it.
Use Charles Proxy
It has a tab called WebSocket that shows all web socket related conversations including frames such as Ping,Pong and Close.
来源：https://stackoverflow.com/questions/39914968/how-to-see-ping-pong-in-web-socket-in-ios