Property: org.zkoss.zkmax.au.websocket.WebSocketEndPoint.pingIntervalSecond

Default: 0 (Turned off)
since 9.5.0

Default: 25 (Turned on)
It means the http session will keep alive during the ping and pong mechanism until the user closes the browser tab or navigates to another browser page.
since 9.6.1

It specifies the interval in second of the ping mechanism described in RFC 6455 when WebSocket connection is enabled.

Only works when WebSocket connection is enabled.