Attempt to create websocket client for browser without using the WebSocket library (https://developer.mozilla.org/en-US/docs/Web/API/WebSocket)
Not working due to FORBIDDEN HEADERS https://developer.mozilla.org/en-US/docs/Glossary/Forbidden_header_name i.e.
browser doesn't allow to modify "Connection" HTTP header to "Upgrade".
Possible solution can be with the Chrome Extensions or Firefox Addons.