아래처럼 복사해서 붙여넣어보세요.

<?
if (!defined("_GNUBOARD_")) exit; // 개별 페이지 접근 불가
?>
<form name='frmsearch1' id="frmsearch1" style='margin:0px;' action = '<?=$g4[path]?>/bbs/board.php'>
<input type="checkbox" name="wr_1" value="9">
<input type="checkbox" name="wr_2" value="80">
<input type="checkbox" name="wr_3" value="700">
<input type="checkbox" name="wr_4" value="6000">
<input type="checkbox" name="wr_5" value="50000">
<input type="checkbox" name="wr_6" value="400000">
<input type="checkbox" name="wr_7" value="3000000">
<input type="checkbox" name="wr_8" value="20000000">
<div>합계: <span id="sumSpan" name="sumSpan" class="stx">0</span></div>


    <!-- 검색 -->
    <div class="board_search">
              <input type='hidden' name='bo_table' value='<?=$bo_table?>' />
              <input type='hidden' name='sca'        value='' />
              <input type='hidden' name='sop'        value='and' />
              <select name='sfl' id='sfl' style="width:100px;">
              <option value="wr_9">계산결과값</option>
              <option value="wr_subject">제목</option>
              </select>
        <input type=text name=stx id="stx" size="20" value=''>
        <input name="image" type="image" src='<?=$board_skin_path?>/img/btn_search.gif' align="absmiddle" border="0" />
    </div>
</form>
 


<script type="text/javascript">
<!--
var sum = 0;

function init(){
var len = frmsearch1.elements.length;
var elm = frmsearch1.elements;

for(i=0;i<len;i++){
    if(elm[i].type=="checkbox"){
      elm[i].onclick = function ck_onclick(){
            if(this.checked) sum += parseInt(this.value);
            else sum -= parseInt(this.value);
                sumSpan.innerText = sum;
                document.getElementById('stx').value = sum;
            }
      }
    }
}

window.onload = init;
-->
</script>