Hi I looking for a documentation or example to connect to socket.io running on nodejs at server side from a pure JS from a client.
I have to remove the socket.io.js lib from the client side.
socket.io provides various transport layers. If you are happy to experiment and are sure that your client supports WebSocket in all cases, then you might be successful in reproducing the WebSocket-based part of the socket.io protocol on the client side. This, however, seems to be a tedious task compared to just using the code that you would re-invent (partly) anyway.
Use socket.io on the client side, or take an entirely different approach, also on the server side.