검색기능 질문드립니다.

head 부분에서 저 빨간색 동그라미친부분 체크하는걸 없애고 검색시 상품만 검색됫스면
좋겟는데 어떻게 수정해야할지 도와주세요!

<!-- 검색 시작 -->
<form name='frmsearch1' style='margin:0px;' onsubmit='return search_submit(this);'>
<input type='hidden' name='sfl' value='wr_subject||wr_content'>
<input type='hidden' name='sop' value='and'>
<input type='hidden' name='stx' value=''>
<select name='search_flag' id='search_flag' class='small'>
<option value='상품'>상품
<option value='게시판'>게시판
</select>
<input type=text name=search_str class='ed' value='<?=stripslashes(get_text($search_str))?>'>
<input type=image src='<?=$g4[path]?>/img/btn_search.gif' border=0 align=absmiddle>&nbsp;
</form>
<script>
function search_submit(f) {
if (f.search_flag.value == '상품') {
f.action = '<?=$g4[shop_path]?>/search.php';
} else {
f.stx.value = f.search_str.value;
f.action = '<?=$g4[bbs_path]?>/search.php';
}
}

<?
if ($search_flag) {
echo "document.getElementById('search_flag').value = '$search_flag';";
}
?>
</script>
<!-- 검색 끝 -->