Note: This feature is available in Web Workers.
The WebSocket.readyState read-only property returns the current state of the WebSocket connection.
A number which is one of the four possible state constants defined on the WebSocket interface:
WebSocket.CONNECTING (0)Socket has been created. The connection is not yet open.
WebSocket.OPEN (1)The connection is open and ready to communicate.
WebSocket.CLOSING (2)The connection is in the process of closing.
WebSocket.CLOSED (3)The connection is closed or couldn't be opened.