Ajax does not receive data in json

Question

Personal I created a function with Ajax that should return the posts that are in the database. Ajax requires a PHP script that responds with a JSON but I get the following message in the browser console

Synchronous xmlhttprequest should not be used on the main thread due to to its detrimental effects on the user experience. For more information http://xhr.spec.whatwg.org/

Follow the front-end code:

$(document).ready(function () {
    var count = 0;
    var value = 4;
    function getOtherPubli() {
        var stringUrl = $(location).attr('href').split("/");
        var type = stringUrl[2];
        var id = stringUrl[3];
        $.ajax({
            method: "POST",
            url: "/sys/etc/other-publi.php",
            data: {noPost: id, q: value, b: count, type: type}

        }).done(function (answer) {
            if (answer.status == 'ok') {
                $('contant-others-publi').html(answer.string);
                count += value;
            } else {
                console.log("System (other post) error. Code: " + answer.status);
            }


        }).fail(function (jqXHR, textStatus) {
            console.log("System (other post) error. Request failed: " + textStatus);

        });
    }
    getOtherPubli();
});

Code in PHP:

<?php

include_once 'sys/lib.php';
include_once 'sys/db/base0.php';

$id = [];
$tl = [];
$cp = [];
$string = '';
$res = ['status'=>null,'string'=>null];

if (isAjax()) {
    $getPost = ["nopost" => (int) $_POST['noPost'], "q" => (int) $_POST['q'], "b" => (int) $_POST['b'], "type" => clrSqli($_GET['type'])];
    $db = connectdb();
    $get = $db->prepare("SELECT id,title,coverofpost FROM `posts` WHERE id <> :notPost AND type = :type ORDER BY `date` DESC LIMIT :begin, :end");
    $get->bindValue(":notPost", $getPost['nopost'], PDO::PARAM_INT);
    $get->bindValue(":begin", $getPost['q'], PDO::PARAM_INT);
    $get->bindValue(":end", $getPost['b'], PDO::PARAM_INT);
    $get->bindValue(":type", $getPost['type'], PDO::PARAM_STR);
    $get->execute();
    if ($get->rowCount() > 0) {
        while ($data = $get->fethc(PDO::FETCH_ASSOC)) {
            array_push($id, $data['id']);
            array_push($tl, $data['title']);
            array_push($cp, $data['coverofpost']);
        }
        $length = count($id);
        for ($i = 0;$i < $length;$i ++) {
            $string .= '<div class="other-publi" data-id="'.$id[$i].'">
                        <div class="limit-img-other-publi">
                            <img class="img-other-post" src="'.$cp[$i].'" alt="FOTO"/>
                        </div>
                        <div class="title-other-publi">
                            <span>'.$tl[$i].'</span>
                        </div>
                     </div>';
        }
        $res['status'] = 'ok';
        $res['string'] = $string;
    } else {
        $res['status'] = 404;
    }
} else {
    $res['status'] = 403;
}
echo json_encode($res,true);