Mine
public text v1 · immutableon *:input:*: {
if ($left($1,1) !isalnum) goto last
msg $active $+(,$r(01,15)) $+ $$1-
halt
:last
}
on *:input:*: {
if ($left($1,1) !isalnum) goto last
msg $active $+(,$r(01,15)) $+ $$1-
halt
:last
}