DENEME 2

============================1.sayfa=================
<?php session_start(); ?>
<!DOCTYPE html>
<html>
<body>

<button type="submit" id="ilacekle">TEST</button>
<input type="text" name="param">
<?php echo $_SESSION["id"];?>
<div class="result"></div>
<script type="text/javascript" src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
<script>
    $(document).ready(function () {
        $("#ilacekle").click(function (event) {
            event.preventDefault();
            var formData = {
                'ilacId': $('input[name=param]').val()
            };
            $.ajax({
                context: this,
                type: 'POST',
                url: 'ajax2.php',
                data: formData,
                dataType: 'json',
                encode: true,
                success: function (data) {
                    console.log(data);
                    $(".result").html(JSON.stringify(data));
                }
            });
        });
    });
</script>
</body>
</html>
============================2.sayfa=================
<?php
session_start();
$_SESSION['id'] = $_POST['ilacId'];
$data['ilacId'] = $_POST['ilacId'];
$data['success'] = true;
$data['message'] = 'Success!';
echo json_encode($data);
?>