Cakephp3 jQuery自动完成

I'm new to CakePHP3 (+stackoverflow) and try to implement autocomplete. I'd like to attach the autocomplete-function to the searchinput in my index.ctp.

1. the request returns all car-objects (ignores the get.term)
2. the response isn't attached to the searchinput

Would be fine to get some help - thanks!

index.ctp

<?php
echo $this->Form->create('Cars');
    echo $this->Form->input('name', [
            'label' => 'Search',
            'id' => 'autocomplete',
            'class' => 'ui-autocomplete'
    ]);
echo $this->Form->button('Search', ['type' => 'submit']);
echo $this->Form->end();
?>
<script>
$("#autocomplete").autocomplete(
    {
        search: function () {},
        source: function (request, response)
        {
            $.ajax(
            {
                source: "/cars/autocomplete",
                dataType: "json",
                data:
                {
                    term: request.term,
                },
                success: function (data)
                {
                    response(data);
                    console.log(data);
                }
            });
        },
        minLength: 2
    });
</script>

CarsController.php

function autocomplete() {
    if ($this->request->is('ajax','get')) {
        $term = $this->request->data["term"];
        $terms = $cars->find('all', [
            'conditions' => ['Cars.name >' => $term],
            'limit' => 10
        ]);

    $data = array();
        foreach($terms as $term) {
            $row = $term->name;
            array_push($data, $row);
        }

        // $this->layout = 'ajax';
        $this->set('terms', $terms);
        echo json_encode($data);
    // return json_encode($data);
    }
    else {
        echo json_encode('Nothings found');
    }
}

Okay, I just found a solution (may be not a perfect?!). Here's my code

index.ctp

<script>
$( function() {
$( "#autocomplete" ).autocomplete({
    minLength: 1,
    source: function( request, response ) {
        $.ajax({
            url: "<?php echo Router::url(['controller' => 'Cars', 'action' => 'autocomplete']);?>" + '?term=' +
                request.term,
                dataType: "json",
                success: function (data)
                {
                    response(data);
                    console.log(data);
                }
          });
      }
  });
});
</script>

CarsController.php action autocomplete

public function autocomplete() {
    $this->autoRender = false;
    $terms = $this->Cars->find('list', array(
            'conditions' => array(
                    'Cars.name LIKE' => trim($this->request->query['term']) . '%'
            )
    ));
    echo json_encode($terms);   
}