open tools => script editor 

in aliases tab paste

lag { .raw -q ping $ticks }


in remote paste

on ^*:pong: { haltdef | if ($calc($ticks - $2) < 1000) { msg $active Lag to $server $+ : $calc($ticks - $2) $+ ms }
if ($calc($ticks - $2) > 999) { msg $active Lag to $server $+ : $round($calc(($ticks - $2) / 1000),2) $+ s } }


then click ok