Strophe.ping.js is a plugin to provide XMPP Ping ( XEP-0199 ).
After you connected sucessfully to the XMPP server you can send a ping to a XMPP client or server:
connection.ping.ping( "[email protected]", success, error, timeout );
You can also add a ping handler to receive pings:
connection.ping.addPingHandler( handler );
Within your ping handler function you surely want to reply with a pong iq:
handler = function( ping ){
...
connection.ping.pong( ping );
...
return true;
}