Yii2 form input field counts with value from db - forms

Question

I do my project in yii2.
I have form which get data from db to dropdown list(using kartik depdtop widget).
First field is "type_of_goods", depending on "type_of_goods" customer receive "goods".
After they are two text input field with "goods_amount" and "total_cost" of goods depends on "goods_amount" (goods_amount * price).
Customer inputs goods amount he wants to buy, or money amount to which he wants to buy and js script shows him value in another field in both cases.
Price value is in goods table in DB.
Can I get goods_id or some information about goods from "goods"-field(to perform db query and get price and put it into js function), or maybe even price to put it into js script which do things that I wrote above.
How can I realize it? Is it right way to do it?
Code:
View
<?php $form = ActiveForm::begin([
'options' => [
'class' => 'form-horizontal col-lg-11',
'enctype' => 'multipart/form-data'
],
]); ?>
<?= $form->field($type_of_goods, 'id')
->dropDownList(
ArrayHelper::map(Type_of_goods::find()->all(), 'id', 'name'),
['id'=>'type_of_goods_id']
);
?>
<?= $form->field($goods, 'id')->widget(DepDrop::classname(), [
'options' => ['id' => 'id'],
'pluginOptions' => [
'depends' => ['type_of_goods_id'],
'placeholder' => 'Choose your goods',
'url' => \yii\helpers\Url::to(['goods/goods-dep-type'])
]
]);
?>
<?= $form->field($goods, 'price')->textInput();
?>
<?= $form->field($order, 'amount')->textInput();
?>
<?php ActiveForm::end(); ?>
Controller:
public function actionGoodsDepType()
{
$out = [];
if (isset($_POST['depdrop_parents'])) {
$parents = $_POST['depdrop_parents'];
if ($parents != null) {
$game_id = $parents[0];
$out = \app\models\Goods::gelGoodsList($goods_type_id);
echo Json::encode(['output' => $out, 'selected' => '']);
return;
}
}
echo Json::encode(['output' => '', 'selected' => '']);
}
Model:
public static function gelGoodsList($type_id)
{
$query = self::find()
->where(['type_id' => $type_id])
->select(['id', 'name'])->asArray()->all();
return $query;
}
public static function getPrice($id)
{
$query = self::find()
->where(['id' => $id])
->select(['price'])->asArray()->one();
return $query;
}

Answer 1

You would need to create an AJAX request each time user inputs new value. This might work well (place at the bottom of the view file):
$this->registerJs("
$('#Type_of_goods-price').on('change', function() { // Should be ID of a field where user writes something
$.post('index.php?r=controller/get-price', { // Controller name and action
input_price: $('#Type_of_goods-price').val() // We need to pass parameter 'input_price'
}, function(data) {
total_price = $.parseJSON(data)['result']; // Let's say, controller returns: json_encode(['result' => $totalPrice]);
$('#Type_of_goods-total').value = total_price; // Assign returned value to a different field that displays total amount of price
}
});
");
You only need to set correct elements' correct IDs and write a method in controller (using this example, it would be controller controller name and actionGetPrice method name).