yii2 ActiveForm 如何动态的添加文本框

[lyp_2008001]

<?php $form = ActiveForm::begin([
    'id' => 'login-form',
    'options' => ['class' => 'form-horizontal','enctype'=>'multipart/form-data'],
    'method' => 'post',
    'action' => ['site/insert'],
    'fieldConfig' => [
        'template' => "{label}\n<div class=\"col-lg-3\">{input}</div>\n<div class=\"col-lg-8\">{error}</div>",
        'labelOptions' => ['class' => 'col-lg-1 control-label'],
    ],
]); ?>

<?= $form->field($model, 'w_title') ?>

<?= $form->field($model, 'w_number')?>

<?= $form->field($model,'w_pic1_url')-> fileInput() ?>

<?= $form->field($model,'w_focus_url')-> dropDownList($vv,['prompt'=>'请选择']) ?>

<?= $form->field($model,'w_focusm_url[]')-> dropDownList($vv1,['prompt'=>'请选择...']) ?>

<?= $form->field($model,'w_focusm_url[]')-> dropDownList($vv1,['prompt'=>'请选择...']) ?>

<?= $form->field($model,'w_focusm_url[]')->dropDownList($vv1,['prompt'=>'请选择..']) ?>


<div class="form-group">
    <div class="col-lg-offset-1 col-lg-11">
        <?= Html::submitButton('提交', ['class' => 'btn btn-primary', 'name' => 'submit-button']) ?>
        <?= Html::resetButton('重置', ['class' => 'btn btn-primary', 'name' => 'submit-button']) ?>
        <?= Html::Button('添加', ['class' => 'btn btn-primary', 'name' => 'submit-button','onclick'=>'javascript:add(‘动态添加文本框’)']) ?>


    </div>
</div>

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

我想请问一下，add函数该如何写啊，用js写吗？？

[sun521]