public function searchintercession($params, $typr)
 {
     $query = Intervenant::find()->where(['typeinter' => $typr]);
     $dataProvider = new ActiveDataProvider(['query' => $query]);
     $this->load($params);
     if (!$this->validate()) {
         // uncomment the following line if you do not want to return any records when validation fails
         // $query->where('0=1');
         return $dataProvider;
     }
     $query->andFilterWhere(['like', 'typeinter', $this->typeinter])->andFilterWhere(['like', 'titre', $this->titre])->andFilterWhere(['like', 'adresse', $this->adresse])->andFilterWhere(['like', 'mail', $this->mail])->andFilterWhere(['like', 'tel', $this->tel]);
     return $dataProvider;
 }
<?php

use yii\helpers\Html;
use yii\helpers\ArrayHelper;
use yii\widgets\ActiveForm;
use yii\grid\GridView;
use yii\data\ActiveDataProvider;
use yii\bootstrap\Dropdown;
use app\models\Bien;
use app\models\Reformer;
use app\models\Intervenant;
/* @var $this yii\web\View */
/* @var $model app\models\Bien */
/* @var $form yii\widgets\ActiveForm */
$dataIntervenant = ArrayHelper::map(Intervenant::find()->where(['typeinter' => 'Don'])->asArray()->all(), 'titre', 'titre');
?>

<div class="bien-formAmort">

    <?php 
$form = ActiveForm::begin();
?>
    
<div class="col-lg-12">
                        <label  class="col-lg-2 control-label"> Unite:</label>
                           <?php 
echo $form->field($model, 'titre', [])->dropDownList($dataIntervenant, ['prompt' => '----------Choisir une unite----------', 'onchange' => '
                                                    $.post( "index.php?r=reformer/listunite&id=' . '"+$(this).val(), function( data ) {   
                                            $( "select#intervenant-titre").html(data );
                                        });'])->label(false);
?>