PHP 數組填充下拉選單：動態生成 Select Options 完整範例

數據結構

<?php
$data = [
    (object)['titulo' => 'Ford',     'valor' => 'opcion1'],
    (object)['titulo' => 'Peugeot',  'valor' => 'opcion2'],
    (object)['titulo' => 'Chevrolet','valor' => 'opcion3'],
    (object)['titulo' => 'Volkswagen','valor' => 'opcion4'],
];
// 也可以是關聯數組：
$data = [
    ['titulo' => 'Ford', 'valor' => 'ford'],
    ['titulo' => 'Peugeot', 'valor' => 'peugeot'],
];
?>

模板中生成 <select>

<select class="select_brand" name="brand" onchange="onChangeBrand(this)">
    <option value="" selected disabled>請選擇品牌</option>
    <?php foreach ($data as $item): ?>
        <option value="<?= htmlspecialchars($item->valor ?? $item['valor']) ?>">
            <?= htmlspecialchars($item->titulo ?? $item['titulo']) ?>
        </option>
    <?php endforeach; ?>
</select>

前端聯動：品牌選中 → 載入車型

<script>
function onChangeBrand(select) {
    const brandId = select.value;
    if (!brandId) return;

    // 1. 顯示載入狀態
    const modelSelect = document.querySelector('select[name="model"]');
    modelSelect.innerHTML = '載入中...';
    modelSelect.disabled = true;

    // 2. AJAX 獲取車型
    fetch(`/api/models?brand_id=${encodeURIComponent(brandId)}`)
        .then(r => r.json())
        .then(list => {
            modelSelect.innerHTML = '請選擇車型' +
                list.map(m => `${m.name}`).join('');
            modelSelect.disabled = false;
        })
        .catch(() => {
            modelSelect.innerHTML = '載入失敗';
            modelSelect.disabled = false;
        });
}
</script>

後端 API 範例（PDO）

<?php
// /api/models.php
header('Content-Type: application/json; charset=utf-8');
$pdo = new PDO($dsn, $user, $pass);
$brandId = $_GET['brand_id'] ?? '';
$stmt = $pdo->prepare("SELECT id, name FROM models WHERE brand_id = ? AND status = 1");
$stmt->execute([$brandId]);
echo json_encode($stmt->fetchAll(PDO::FETCH_ASSOC));
?>

進階：分組選單 <optgroup>

<?php
$grouped = [
    '國產品牌' => [
        ['titulo' => '比亞迪', 'valor' => 'byd'],
        ['titulo' => '吉利',   'valor' => 'geely'],
    ],
    '合資品牌' => [
        ['titulo' => '大眾', 'valor' => 'vw'],
        ['titulo' => '豐田', 'valor' => 'toyota'],
    ],
];
?>
<select name="brand">
    <?php foreach ($grouped as $group => $items): ?>
        <optgroup label="<?= htmlspecialchars($group) ?>">
            <?php foreach ($items as $item): ?>
                <option value="<?= htmlspecialchars($item['valor']) ?>">
                    <?= htmlspecialchars($item['titulo']) ?>
                </option>
            <?php endforeach; ?>
        </optgroup>
    <?php endforeach; ?>
</select>

安全與最佳實踐