ws:
This is the new URL schema for WebSocket connections. There is also wss:
for secure WebSocket connection the same way https:
is used for secure HTTP connections.
By Definition
The WebSocket specification defines an API establishing "socket" connections between a web browser and a server.
In plain words
There is an persistent connection between the client and the server and both parties can start sending data at any time. That is a full-duplex communication channels over a single TCP connection.
Take a look here for API and here for web sockets basics and here for a simple live demo of it.