To see what you are getting back from your script add an alert() to your javascript:
$.get("suggest.pl", {word: $(this).val()}, function(data){
alert(data);
$("#myWord").empty();
$("#myWord").html(data);
});
You say earlier that you already have the script that deals with the db, so instead of the
echo in PHP you just need
print in Perl, something like:
print $q->header;
while (my $row = $sth->fetchrow_hashref) {
my $word = $row->{'crps_word'};
my $prob = $row->{'crps_probability'};
my $str = $prob."----".$word;
print qq|<option value="$word">$str</option>|;
}