선택삭제 버튼을 추가했는데 작동이 안됩니다. 채택완료

        <?php if ($rss_href || $write_href) { ?>

        <ul class="btn_bo_user">

            <?php if ($rss_href) { ?><li><a href="<?php echo $rss_href ?>" class="btn_b01 btn"><i class="fa fa-rss" aria-hidden="true"></i> RSS</a></li><?php } ?>

            <?php if ($admin_href) { ?><li><a href="<?php echo $admin_href ?>" class="btn_admin btn"><i class="fa fa-cog" aria-hidden="true"></i></a></li><?php } ?>

            <?php if ($write_href) { ?><li><a href="<?php echo $write_href ?>" class="btn_b02 btn"><i class="fa fa-pencil" aria-hidden="true"></i> 글쓰기</a></li><?php } ?>

        </ul>

        <?php } ?></p>

<p>

        <form name="fboardlist" id="fboardlist" action="<?php echo G5_BBS_URL; ?>/board_list_update.php" onsubmit="return fboardlist_submit(this);" method="post">

        <?php if ($rss_href || $is_checkbox || $write_href) { ?>

        <ul class="btn_bo_user">

            <?php if ($rss_href) { ?><li><a href="<?php echo $rss_href ?>" class="btn_b01 btn"><i class="fa fa-rss" aria-hidden="true"></i> RSS</a></li><?php } ?>

            <?php if ($is_checkbox) { ?><li><button type="submit" name="btn_submit" value="선택삭제" onclick="document.pressed=this.value" class="btn btn_admin"><i class="fa fa-trash-o" aria-hidden="true"></i> 선택삭제</button></li><?php } ?>

            <?php if ($admin_href) { ?><li><a href="<?php echo $admin_href ?>" class="btn_admin btn"><i class="fa fa-cog" aria-hidden="true"></i></a></li><?php } ?>

            <?php if ($write_href) { ?><li><a href="<?php echo $write_href ?>" class="btn_b02 btn"><i class="fa fa-pencil" aria-hidden="true"></i> 글쓰기</a></li><?php } ?>

        </ul>

        <?php } ?>

        </form></p>

<p>