$content .= "<p id=\"more{$id}_$no\" class=\"moreless_fold\"><span style=\"cursor: pointer;\" onclick=\"toggleMoreLess(this, '{$id}_$no','$more2','$less2'); return false;\">$more</span></p><div id=\"content{$id}_$no\" class=\"moreless_content\" style=\"display: none;\">$full</div>";를 다음처럼 수정하시면 될 것 같습니다.
$content .= "<p id=\"more{$id}_$no\" class=\"moreless_top\"><span style=\"cursor: pointer;\" onclick=\"toggleMoreLess(this, '{$id}_$no','$more2','$less2'); return false;\">$less</span></p><div id=\"content{$id}_$no\" class=\"moreless_content\" style=\"display: block;\">$full</div><p id=\"less{$id}_$no\" class=\"moreless_bottom\"><span onclick=\"toggleMoreLess(this, '{$id}_$no', '$more2', '$less2'); return false;\" style=\"cursor: pointer;\">$less</span></p>";