if Pos('%', s) = 0 then begin
        Result := s;
        exit;
    end;
    sb.Init;
    i := 1;
    while (i <= Length(s)) do begin
        c := s[i];
        if c = '%' then begin
            c := Chr(StrToInt('$' + Copy(s, i + 1, 2)));
            Inc(i, 2);
        end;
        sb.Add(c);
        Inc(i);
    end;
    Result := sb.Value