I keep reading about ping/pong messages in websockets to keep the connection alive, but I'm not sure what they are. Is it a distinct frame type? (I don't see any methods on a javascript WebSocket object in chrome related to ping-pong). Or is it just a design pattern (e.g. I literally send "ping" or any other string to the server and have it respond). Is ping-pong at all related to continuation frames?

The reason I ask is I'm using a python framework that runs behind Mongrel2, so I'm wondering if there's a way to send Mongrel2 a specific ping/pong message that would tell it to keep the connection alive without my python app needing to worry about it. Analogous to a having a separate HTTP method for it, I guess. And I imagine a dedicated ping/pong message frame could be simpler (less load on server and network) than the string "ping", though that probably wouldn't matter too much.

EDIT: I just looked at RFC 6455 and it looks like Ping and Pong are definitely control frame types with their own opcodes. So how do I send a Ping frame from javascript in Chrome?