Strophe.ping.js

Strophe.ping.js is a plugin to provide XMPP Ping
( XEP-0199 ).

Usage

After you connected sucessfully to the XMPP server you can send a ping to a XMPP
client or server:

connection.ping.ping( "serviceJID@server.org", 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;
}