I've entered echo.websocket.org as it was suggested, opened Network tab and WS filter in Chrome Developer Tools, but I do not see any frames. I see connection entries, but Frames tab always stays empty. Is there anything special I should do to see the frames?
Screenshot:
Did you send any data on the page? You need to try sending a message after clicking Connect:
There is also a useful area in Chrome where you can view all your active sockets:
You can access it at here: chrome://net-internals/#events&q=type:SOCKET%20is:active
Update:
After seeing your newly added screenshot, it looks like your Data table is squashed up and you need to drag it down to see the entries.
Click Network, WS, select the original HTTP connection and then click the Frames tab. Be aware that the content of this tab may be hidden by another pane, so you need to drag the bar down to see the WebSocket frames.
来源：https://stackoverflow.com/questions/37413092/how-to-inspect-websocket-frames-in-chrome-properly