폼 select 에서 선택 option값 외에 다른(?)값을 같이 전달하는 방법을 질문드립니다

<form name="fsearch"method="get" style="margin:0px;">      <input type="hidden" name="gr_id" value="<?=$gr_id?>">      <input type="hidden" name="nobnr" value="nobnr">      <input type="hidden" name="sfl" value="wr_subject">      <input type="hidden" name="sop" value="or">      <input type="hidden" name="bo_table" value="<?=$bo_table?>" readonly>      구분      <select name="sca" id="sca">      <option value=''>선택하세요</option>      <?        $sql3 = "select bo_table, bo_subject, bo_category_list from $g4[board_table] where gr_id = '$gr_id' order by bo_order_search ";         $rst3 = sql_query($sql3);        for ($k=0; $row3=sql_fetch_array($rst3); $k++)        {          //카테고리 메뉴 시작          if ($row3[bo_category_list] ) {            echo "<option value='' disabled style='background:#efefef;'>$row3[bo_subject]</option>" ;                         $ca_menu = explode("|",$row3[bo_category_list]);                          for ($i=0; $i<count($ca_menu); $i++)             {              if ($sca==$ca_menu[$i]) {                $ca_menu[$i] .= "<option value='$ca_menu[$i]' selected onclick='bo_select({$row3[bo_table]});'>   $ca_menu[$i]</option>" ;              }              else              {                $ca_menu[$i] .= "<option value='$ca_menu[$i]' onclick='bo_select({$row3[bo_table]});'>   $ca_menu[$i]</option>" ;              }              echo $ca_menu[$i] ;            }          }                     // 카테고리 메뉴 끝        }?>      </select> ... <script>function bo_select(val){  var f = document.fsearch ;     f.bo_table.value = val ;} </script>