If you want to disable a specific script event, you could put the event inside of a group.

Code:

#OnJoinNotice on

on !*:JOIN:#: {
  .notice $nick Welcome to my channel $nick $+ !
}

#OnJoinNotice end

on *:TEXT:*:#: {
  if ($1 == !noticeoff) .disable #OnJoinNotice
  elseif ($1 == !noticeon) .enable #OnJoinNotice
  .notice $nick ON JOIN Notice is $group(#OnJoinNotice)
}


/help /disable
/help /enable
/help $group