Cakephp 3.4 JQuery , ajax and $_POST - php

Question

I have a big problem with Cakephp 3.4
This is my controller:
//$id=$_POST["idString"]; ---- how can i do this in cakephp?
$id = $this->request->data('idString');
$posts = $this->Posts->find('all', array(
'conditions' => array(
'Animal_id' => $id
)
));
$this->set(compact('posts'));
And this is my script
$(document).ready(function() {
$(".dropdown-item").click(function(){
idString = $(this).attr("value");
alert(idString);
$.ajax({
type: "POST",
url: "<?php echo \Cake\Routing\Router::url(array('controller' => 'MyControllerName', 'action' => 'index')); ?>",
data: "idString="+idString,
success: function(result){
$("#show").html(result);
}
});
});
});
And this is my index :
<?php foreach($posts as $post):?>
<li><?= $post->title, $post->text; ?></li>
<?php endforeach ?>
<div id="show">
<--show id-->
</div>
And error that I have is
Deprecated (16384): Controller::$layout is deprecated. Use $this->viewBuilder()->setLayout() instead. [CORE\src\Controller\Controller.php, line 383]
And it returns me one div 2 time.

Answer 1

Cakephp 3.4 have in src/Template/Layout/ajax.ctp look there if don't have $this->fetch('content'); if yes then delete it or comment.