How to post data of selected rows of a dataTable to php controller through an JQuery ajax call

I used this code from https://datatables.net/examples/api/select_row.html to select multiple rows

$('#table tbody').on('click','tr', function(){
    $(this).toggleClass('selected');
});

This is the initialization for jquery datatable

$(document).ready(function() {

    //datatables
    table = $('#table').DataTable({ 

        "processing": true, //Feature control the processing indicator.
        "serverSide": true, //Feature control DataTables' server-side processing mode.
        "order": [], //Initial no order.

        dom: 'Bfrtip',
        buttons: [
            //'copyHTML5', 'csvHTML5', 'excelHTML5', 'pdfHTML5', 'printHTML5'
            'copy', 'csv', 'print'//, 'excel', 'pdf'
        ],
        // Load data for the table's content from an Ajax source
        "ajax": {
            "url": "<?php echo site_url('person/ajax_list')?>",
            "type": "POST"
        },

        //Set column definition initialisation properties.
        "columnDefs": [
            { 
                "targets": [ -1 ], //last column
                "orderable": false, //set not orderable
            },
            { 
                "targets": [ -2 ], //2 last column (photo)
                "orderable": false, //set not orderable
            },
        ],

    });

    $('#table tbody').on('click','tr', function(){
        $(this).toggleClass('selected');
    });
}

Now I want to send these selected rows to php controller through an ajax call so I can then create a csv file with these selected rows data.

I created a button which on click calls the following function where the ajax call is made

    function create_PO()
    {
        $('#btnSel').text('creating...');
        $('#btnSel').attr('disabled',true);

        var url = "<?php echo site_url('person/create_csv')?>";
        var selectedData = table.rows('.selected').data();
        //console.log(selectedData);
        //alert(selectedData.length);
        newData = new Array();
        for(i=0;i<selectedData.length;i++){
            newData.push(selectedData[i]);
        }
        jsonData = JSON.stringify({data : (selectedData[0].slice(0,5))});
        //console.log(jsonData);
        //newData = $.serialize(newData);
        //console.log(newData);

        $.ajax({
            url : url,
            type: "POST",
            data: jsonData,
            contentType: false,
            processData: false,
            dataType: "JSON",
            success: function(data)
            {
                /*data.forEach(function(e){
                    console.log(e);
                })*/
                console.log(data);
                // alert("sheet created successfully");

                // $('#btnSel').text('create');
                // $('#btnSel').attr('disabled',false);

            },
            /*error: function (jqXHR, textStatus, errorThrown)
            {
                alert('Error creating file');
            }*/

        });

    }}

when I do echo($_POST) from the controller, the response is showing empty array. Also, the console.log(data) function in success option of ajax is also not printing anything. Can anybody pls tell me what the problem is? Thanks!