Reply To: Update chart with new date

[rcweb]

Thank you very much for your reply to my inquiry and your offer of help Mohan.
i try use post to send start and end date user select to php page to get date from database base date user selected:

var startDate = picker.startDate.format(‘YYYY-MM-DD’);
var endDate = picker.endDate.format(‘YYYY-MM-DD’);
// alert(startDate = ${startDate}, endDate = ${endDate});

$.ajax({
url : 'chart.php',
type : 'POST',
data : {startDate:startDate,endDate:endDate},
success : function(data) {
 $.getJSON("chart.php", function (data) {

var chart = new CanvasJS.Chart("chartContainer", {
 data: [
 {
							   
 indexLabel: " {y}",
 indexLabelFontSize: 16,

 dataPoints: data
 }
 ]
 });

  chart.render();
 });
 }
 });

But the chart does not appear.
this php code :

 include("config.php");

if (isset($_POST['startDate'])) {

$startDate = $_POST['startDate'];
$endDate = $_POST['endDate'];
//echo   $startDate;
 
$data_points = array();

    $result = mysqli_query($con, "SELECT sub, main, SUM(amount) AS total FROM data WHERE payment_date BETWEEN '$startDate' AND '$endDate' GROUP BY sub, main order by total desc LIMIT 15");

    while($row = mysqli_fetch_array($result))
    {        
        $point = array("label" => $row['sub'] , "y" => $row['total']);

        array_push($data_points, $point);        
    }

    echo json_encode($data_points, JSON_NUMERIC_CHECK);

}