$result = mysql_query("SELECT * FROM tb_estados");
      $cl = mysql_query("SELECT id FROM tb_estados WHERE uf IN (SELECT DISTINCT uf FROM tb_cidades ci JOIN tb_comarcas co ON ci.id = co.cidade)");
      for($ests=array();$row = mysql_fetch_array($cl);$ests[]=$row["id"]);
       while($row = mysql_fetch_array($result) ){
            echo "<option value='".$row['id']."' " . (in_array($row["id"], $ests)?"class='cl'":"") . ">".$row['nome']."</option>";