ca_id 조건문 채택완료

안녕하세요 고수님들

<ul class="sub_02_01">
    <li><a href="<?php echo G5_URL?>/shop/list.php?ca_id=10"><img src="<?php echo G5_URL?>/sub/img/icon-new0001.png"><br>ALL</a></li>
    <li><a href="<?php echo G5_URL?>/shop/list.php?ca_id=1010"><img src="<?php echo G5_URL?>/sub/img/icon-new0002.png"><br>댓글</a></li>
    <li><a href="<?php echo G5_URL?>/shop/list.php?ca_id=1020"><img src="<?php echo G5_URL?>/sub/img/icon-new0003.png"><br>팔로워</a></li>
    <li><a href="<?php echo G5_URL?>/shop/list.php?ca_id=1030"><img src="<?php echo G5_URL?>/sub/img/icon-new0004.png"><br>좋아요</a></li>
    <li><a href="<?php echo G5_URL?>/shop/list.php?ca_id=1040"><img src="<?php echo G5_URL?>/sub/img/icon-new0005.png"><br>인스타 마케팅</a></li>
</ul>

이렇게 코드가 작성되어 있는데요 ca_id 별로 if 조건문을 줘서 li의 border색상을 변경하려고 합니다 

<ul class="sub_02_01">
    <li <?php if($ca_id=="10") echo "class='on'";?>><a href="<?php echo G5_URL?>/shop/list.php?ca_id=10"><img src="<?php echo G5_URL?>/sub/img/icon-new0001.png"><br>ALL</a></li>
    <li><a href="<?php echo G5_URL?>/shop/list.php?ca_id=1010"><img src="<?php echo G5_URL?>/sub/img/icon-new0002.png"><br>댓글</a></li>
    <li><a href="<?php echo G5_URL?>/shop/list.php?ca_id=1020"><img src="<?php echo G5_URL?>/sub/img/icon-new0003.png"><br>팔로워</a></li>
    <li><a href="<?php echo G5_URL?>/shop/list.php?ca_id=1030"><img src="<?php echo G5_URL?>/sub/img/icon-new0004.png"><br>좋아요</a></li>
    <li><a href="<?php echo G5_URL?>/shop/list.php?ca_id=1040"><img src="<?php echo G5_URL?>/sub/img/icon-new0005.png"><br>인스타 마케팅</a></li>
</ul>

이런식으로 작성 했는데 전혀 먹지 않는 상황이라 요청 드립니다.ㅠㅠ