How to export or download csv file using ajax?

Question

I have a problem with my code downloading csv file. I can get the data but i can't download the csv file. Here is my ajax code:

// Export

   $('#export_csv').click(function(){
    var checkbox = $('.checkbox:checked');
    if(checkbox.length > 0)
    {
        var checkbox_value = [];
        $(checkbox).each(function(){
            checkbox_value.push($(this).val());
        });

        $.ajax({
            url:"csv_action.php",
            method:"POST",
            data:{action:'export_csv'},
            dataType:'json',
            success:function(data)
            {
                $("#select_all").prop('checked', false); 

                $('#message').html(data);
                
                setTimeout(function(){

                    $('#message').html('');

                }, 5000);
            }
        });
    }
    else
    {
        alert("Please select at least one records");
    }
});

Here is my php file code: The output for this code is the data that i fetch from the database and the data of the student i selected from data table. I tried several methods changing the data type is response and function(success)

// Export CSV

    if($_POST["action"] == 'export_csv')
    {
        $filename = 'reports.csv';

        header("Content-type: text/csv");
        header("Content-Disposition: attachment; filename=$filename");
        header("Pragma: no-cache");
        header("Expires: 0");
                    
        for($count = 0; $count < count($_POST["checkbox_value"]); $count++)
        {

            $object->query = "
            SELECT * FROM tbl_student WHERE
            s_scholar_stat = ''
            ";

            $object->execute();
            $result = $object->get_result();

            $content = array();
            $title = array("Student ID", "First Name", "Middle Initial", "Last Name", "Date of Birth", "Account Status");
            foreach ($result as $rows) {
                $row = array();
                $row[] = $rows["ss_id"];
                $row[] = $rows["sfname"];
                $row[] = $rows["smname"];
                $row[] = $rows["slname"];
                $row[] = $rows["sdbirth"];
                $row[] = $rows["s_account_status"];
                
                $content[] = $row;
                
            }
        }
        $output = fopen('php://output', 'w');
        fputcsv($output, $title);
        foreach ($content as $con) {
            fputcsv($output, $con);
        }
        fclose($output);
        echo '<div class="alert alert-success">Selected Student Data Exported in CSV 
        Successfully</div>';
    }