YII2 实现dropDownList 联动事件

<div class="main-form">

<?php $form = ActiveForm::begin(); ?>


<?= $form->field($model, ‘cid‘)->dropDownList(
\common\models\service\common\Category::getCateOptions(),
[
‘prompt‘ => ‘请选择单位‘,
‘onchange‘=>‘
$.post("/carousel/main/cate?id=‘.‘"+$(this).val(),function(data){
$("select#main-aid").html(data);
});‘,
]
)->hint(‘父级，必选‘) ?>
<?= $form->field($model, ‘aid‘)->dropDownList( \common\models\service\common\Category::getCateOptions(), [‘prompt‘ => ‘请选择子级‘]) ?>
<div class="form-group">
<?= Html::submitButton(‘Save‘, [‘class‘ => ‘btn btn-success‘]) ?>
</div>

<?php ActiveForm::end(); ?>

</div>

public function actionCate($id)
{
$departments = Category::find()
->where([‘parent_id‘ => $id])
->asArray()
->all();

if(!$departments){
echo "<option value=‘" . 0 . "‘>" . "</option>";
}
foreach ($departments as $department) {
echo "<option value=‘" . $department[‘id‘] . "‘>" . $department[‘name‘] . "</option>";
}
}