Synopsis:

on [<modes>]mode [<serial#>] [-|^]<match> { <action> }

Description:

This hook is triggered whenever the client observes a mode change on a channel, or whenever the client changes its modes.

$0	nickname of person issuing mode change
$1	channel or nickname affected by mode change
$2	modes changed
$3-	arguments to modes (if any)

To distinguish between user modes and channel modes:

 on ^mode "*" {
    if ( [$1] == N ) {
       xecho -b User mode change for $1: $2-
    } {
       xecho -b Mode change for $1 by $0: $2-
    }
 }