echo -a $chan(#).onjoin doesnt work

to get the topic i do $chan(#).topic

how do i get the onojin message?

A channel that has an onjoin propped uses on ^1:TEXT:*:#:{ to get it.

But you can't retrieve the onjoin on it's own when in the channel, you have to do //PROP #chan * to show all of it's properties

alot of the time, an onjoin message is set through chanserv using a notice...

so use ON NOTICE to catch it

Judging by pouncer's recent posts suggests he used IRCX
They use /prop