How to implement Ping/Pong request for webSocket connection alive in javascript?

I use websocket in javascript. But the connection close after one minute.

I am wondering somethings:

1- Is not Websocket naturaly providing with Ping/Pong messages not to close the connection? I think it have to. Otherwise what is the difference between websocket and TCP connection?

2- If I have to send the ping/pong messages, how is the ping message sent? What am I need to be? Is WebSocket object provide a ping method? Or should I call a method as websocket.send("ping") ? I am use naturaly WebSocket object in javascipt.

3- Should the server respond to Ping requests with Pong? Should this be implemented separately on the server side?

Note:Sorry for my english.