如何使用php查找上一项并向其添加类

我有一个名为“current menu”的类，我想找到它以前的同级，并添加一个名为“previous menu”的类，如何仅用php实现它

我可以用jquery来实现这一点

$("#menu-header .current-menu").parent().prev().find('a').addClass('current-previous');

但是在客户端添加上一个类的速度很慢，所以我考虑使用服务器端对其进行归档。可能吗

这是我的html和php代码，生成“第一个菜单”、“当前菜单”和“最后一个菜单”

<?php
foreach($items as $index => $item):
?>

<li><a href="#"<?php 
if ($parent->pg_url == $item['pg_url']) echo ' class="current-menu"';
elseif($index == ($total_items - 1)) echo ' class="last-menu"'; 
elseif($index == '0') echo ' class="first-menu"';
?>><?php echo $item['mnu_name'];?></a></li>

<?php endforeach;?>

---

这是解决办法。我假设有些项目可能有两个类

<?php
$items[0]['class'] = "first_menu ";
$items[$total_items - 1]['class'] = "last-menu ";

foreach ($items as $index => &$item) {
    if (!$item['class']) {
        $item['class'] = '';
    }
    if ($parent->pg_url == $item['pg_url']) {
        $item['class'] .= "current-menu ";
        if ($index > 0) {
            $items[$index - 1]['class'] .= "previous-menu ";
        }
    }
}

foreach($items as $index => $item):
?>

<li><a href="#"<?php 
if ($item['class']) echo ' class="' . trim($item['class']) . '"';
?>><?php echo $item['mnu_name'];?></a></li>

<?php endforeach;?>

<li><a href="#">How to visit</a></li>

<li><a href="#" class="previous-menu">How to visit</a></li>

Array
(
    [0] => Array
        (
            [mnu_id] => 1
            [mnu_name] => Home
            [mnu_url] => 
            [mnu_additional] => 
            [mnu_order] => 1
            [pg_url] => home
        )

    [1] => Array
        (
            [mnu_id] => 5
            [mnu_name] => About
            [mnu_url] => 
            [mnu_additional] => 
            [mnu_order] => 2
            [pg_url] => about
        )

    [2] => Array
        (
            [mnu_id] => 6
            [mnu_name] => Venues
            [mnu_url] => 
            [mnu_additional] => 
            [mnu_order] => 3
            [pg_url] => venues
        )

    [3] => Array
        (
            [mnu_id] => 3
            [mnu_name] => How to visit
            [mnu_url] => 
            [mnu_additional] => 
            [mnu_order] => 4
            [pg_url] => how to visit
        )

    [4] => Array
        (
            [mnu_id] => 2
            [mnu_name] => Project Archive
            [mnu_url] => 
            [mnu_additional] => 
            [mnu_order] => 5
            [pg_url] => projects
        )

    [5] => Array
        (
            [mnu_id] => 8
            [mnu_name] => Active Space
            [mnu_url] => 
            [mnu_additional] => 
            [mnu_order] => 6
            [pg_url] => active space
        )

    [6] => Array
        (
            [mnu_id] => 4
            [mnu_name] => Contact
            [mnu_url] => 
            [mnu_additional] => 
            [mnu_order] => 7
            [pg_url] => contact
        )

    [7] => Array
        (
            [mnu_id] => 7
            [mnu_name] => News
            [mnu_url] => 
            [mnu_additional] => 
            [mnu_order] => 8
            [pg_url] => 
        )

    [8] => Array
        (
            [mnu_id] => 9
            [mnu_name] => Resources
            [mnu_url] => 
            [mnu_additional] => 
            [mnu_order] => 9
            [pg_url] => resources
        )

)

<?php
$items[0]['class'] = "first_menu ";
$items[$total_items - 1]['class'] = "last-menu ";

foreach ($items as $index => &$item) {
    if (!$item['class']) {
        $item['class'] = '';
    }
    if ($parent->pg_url == $item['pg_url']) {
        $item['class'] .= "current-menu ";
        if ($index > 0) {
            $items[$index - 1]['class'] .= "previous-menu ";
        }
    }
}

foreach($items as $index => $item):
?>

<li><a href="#"<?php 
if ($item['class']) echo ' class="' . trim($item['class']) . '"';
?>><?php echo $item['mnu_name'];?></a></li>

<?php endforeach;?>