스크립트 질문입니다..

<tr>
                <th scope="row">인테리어</th>
                <td>
                    <ul class="btn_area nine_column after">
                        <li class="btn_li">
                            <input id="a" type="checkbox" name="aya1"  value="소폭 합지">
                            <label for="a">소폭 합지</label>
                        </li>
                        <li class="btn_li">
                            <input id="b" type="checkbox" name="aya1"  value="광폭 합지">
                            <label for="b">광폭 합지</label>
                        </li>
                        <li class="btn_li">
                            <input id="c" type="checkbox" name="aya1"  value="실크 벽지">
                            <label for="c">실크</label>
                        </li>
                        <li class="btn_li">
                            <input id="d" type="checkbox" name="aya1"  value="고급실크 벽지">
                            <label for="d">고급실크</label>
                        </li>
                        <li class="btn_li">
                            <input id="e" type="checkbox" name="aya1"  value="천연벽지">
                            <label for="e">천연벽지</label>
                        </li>
                    </ul>
                </td>
            </tr>
            <tr>
                <th scope="row">건설</th>
                <td>
                    <ul class="btn_area nine_column after">
                        <li class="btn_li">
                            <input id="f" type="checkbox" name="aya2"  value="몰딩">
                            <label for="f">몰딩</label>
                        </li>
                        <li class="btn_li">
                            <input id="g" type="checkbox" name="aya2"  value="걸레받이">
                            <label for="g">걸레받이</label>
                        </li>
                        <li class="btn_li">
                            <input id="h" type="checkbox" name="aya2"  value="문,문틀">
                            <label for="h">문,문틀</label>
                        </li>
                        <li class="btn_li">
                            <input id="i" type="checkbox" name="aya2"  value="아트월">
                            <label for="i">아트월</label>
                        </li>
                        <li class="btn_li">
                            <input id="j" type="checkbox" name="aya2"  value="기타">
                            <label for="j">기타</label>
                        </li>
                    </ul>
                </td>
            </tr>
            <div id="btn">버튼</div>
            <div id="content"></div>
<script type="text/javascript">
    $(function(){
        $("#btn").click(function(){
        for (i = 1; i <=2 ; i ++ ){ 
                var f = "aya"+i;
            $("input[name="+f+"]:checked").each(function() {
                f += $(this).val()+",";
            });
            }
            $("#content").html(f);
        })
    })
</script>