awo-hamburg-intranet/module/knowledgecenter_update/Views/post_listform.php

<?php
// post_listform.php

// Redirect-URL für den Zurück-Button bzw. Navigation
$redirectURL = isset($_GET['redirectURL']) ? $_GET['redirectURL'] : '?action=Category';
// Kategorien für das Dropdown holen (state = 1)
$catsQuery = "
  SELECT c.id, t.title
  FROM knowledgecenter_categories_update AS c
  LEFT JOIN knowledgecenter_category_translations AS t
    ON t.category_id = c.id AND t.language_id = $languageId
  ORDER BY t.title ASC
";
$catsResult = mysqli_query($GLOBALS['mysql_con'], $catsQuery);
$allCategories = [];
while ($r = mysqli_fetch_assoc($catsResult)) {
    $allCategories[] = $r;
}
?>
<div class="titlebar">
    <div>
        <a title="<?= $translation->get("back") ?>" href="?action=List">←</a>
        <h1><?= $translation->get("post_list") ?> <span id="postCount"></span>

        </h1>
        <?php if (get_permission_state('r-wiki', $GLOBALS['main_contact']['master_mandant_id'], $GLOBALS['main_contact']['id']) == 1) { ?>
            <a href="?action=NewPost" class="post-action-btn green">+</a>
        <?php } ?>
    </div>
    <div>
        <select id="categoryFilter">
            <option value=""><?= $translation->get("all_categories") ?></option>
            <?php foreach ($allCategories as $cat): ?>
                <option value="<?= $cat['id'] ?>">
                    <?= htmlspecialchars($cat['title'] ?: "ID:{$cat['id']}") ?>
                </option>
            <?php endforeach; ?>
        </select>
        <input type="search" id="searchQuery" placeholder="<?= $translation->get("search_placeholder") ?>" />
    </div>
</div>

<div id="postListContainer" class="wiki-list">
</div>


<script>
    var myRedirectURL = window.location.href;
    var debounceTimer;

    function loadPostList() {
        var searchQuery = $('#searchQuery').val();
        var categoryId = $('#categoryFilter').val();    // neu

        $.ajax({
            url: '/module/knowledgecenter_update/Ajax/Ajax.php',
            type: 'POST',
            data: {
                action: 'get_post_list',
                language_code: '<?= $languageCode ?>',
                language_id: '<?= $languageId ?>',
                redirectURL: myRedirectURL,
                query: searchQuery,
                category_id: categoryId      // hier mitgeben
            },
            dataType: 'json',
            beforeSend: function () { $('#overlayLoader').show(); },
            complete: function () { $('#overlayLoader').hide(); },
            success: function (response) {
                if (response.success) {
                    $('#postListContainer').html(response.html);
                    var c = parseInt(response.count || 0, 10);
                    $('#postCount').text('(' + c + ')');
                } else {
                    alert('Fehler: ' + response.error);
                }
            },
            error: function (xhr, status, error) {
                console.error('AJAX-Fehler:', error);
            }
        });
    }

    $(document).ready(function () {

        loadPostList();

        $('#searchQuery').on('input', function () {
            clearTimeout(debounceTimer);
            debounceTimer = setTimeout(loadPostList, 300);
        });

        $('#categoryFilter').on('change', loadPostList);
    });
</script>