Well I had made this because I had wanted to look at mIRC's ascii table, but didn't want to manually /echo everything, so I made this. I haven't actually got to look at it yet because every time I try, my mIRC freezes. Oh well, probably should've expected that when you're /echoing 9 hundred million characters. If you can actually run this script without mIRC freezing, well, you've got a VERY good computer. Better than mine anyway. Lol. If you have a better way, that would be appreciated.
Update: Thanks to PuNkTuReD, I got something working. Thanks for the idea.

alias characters {
  if (!$1) { 
    echo Not enough parameters.
  }
  if ($1) && ($2) && ($1 isnum) && ($2 isnum) && ($1 <= $2) { 
    var %x = $1
    while (%x <= $2) {
      echo -a Character: $chr(%x) = $+($chr(36),$chr(99),$chr(104),$chr(114),$chr(40),%x,$chr(41))
      inc %x
    } 
  }
  if ($1) && ($2) && ($1 !isnum) && ($2 !isnum) { 
    echo -a $1 and $2 aren't numbers.
  }
  if ($1) && ($1 isnum) && ($2) && ($2 !isnum) {
    echo -a $2 isn't a number, but $1 is.
  }
  if )($1) && ($1 !isnum) && ($2) && ($2 isnum) {
    echo -a $1 isn't a number, but $2 is.
  }
  if ($1) && (!$2) {
    echo Not enough parameters.
  }
  if ($1) && ($2) && ($1 isnum) && ($2 isnum) && ($1 >= $2) { 
    echo -a Sorry, $2 is smaller than $+($1,.)
  }
}