You forgot the htmlfrm alias.
htmlfrm { var %i = 1,%r while (%i <= $len($1-)) { if ($mid($1-,%i,1) isalnum) { %r = %r $+ $ifmatch } else { %r = %r $+ % $+ $base($asc($mid($1-,%i,1)),10,16,2) } inc %i } return %r }