It is possible to access the VNC console form the WEB browser and without having VNC client installed. For that purpose websockify proxy is used (formerly named wsproxy) and it part of the noVNC project. At the most basic level, websockify just translates WebSockets traffic to normal socket traffic. Websockify accepts the WebSockets handshake, parses it, and then begins forwarding traffic between the client and the target in both directions.
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