Doubts about parameter in the URL - php

Question

I have the following form to the address below:
http://localhost/myapp/web/index.php?r=cashbook%2Faccomplishment
$form = ActiveForm::begin([
'id' => 'accomplishment-form',
'options' => ['class' => 'form-horizontal'],
'action' => Url::to(['/cashbook/accomplishment']),
'method' => 'get',
]);
$form->field($model, 'category_id')->dropDownList(ArrayHelper::map(
Category::find()->where(['user_id' => Yii::$app->user->identity->id])
->orderBy("desc_category ASC")
->all(), 'id_category', 'desc_category'),
['onchange'=>'this.form.submit()','prompt'=>'-- Select --']);
ActiveForm::end();
Who processes and generates the following URL:
http://localhost/myapp/web/index.php?r=cashbook%2Faccomplishment&Cashbook%5Bcategory_id%5D=18
But I need only the category_id value (selected in dropDownList). That is, the URL should be:
http://localhost/myapp/web/index.php?r=cashbook%2Faccomplishment&category_id=19
How to stay that way or get just the category_id

Answer 1

In view add registerJs:
$this->registerJs('var submit = function (val){
if (val > 0) {
window.location.href = "' . Url::to(['/cashbook/accomplishment']) . '/?category_id=" + val;
}
}', View::POS_HEAD);
And not use ActiveForm::begin... and all your code. Instead of use this:
echo Html::activeDropDownList($model, 'id_category', ArrayHelper::map(
Category::find()->where(['user_id' => Yii::$app->user->identity->id])
->orderBy("desc_category ASC")
->all(), 'id_category', 'desc_category'), ['onchange'=>'submit(this.value);','prompt'=>'-- Select --']);