$nestedData[] = '<button type="button" class="delbtn btn btn-danger btn-xs" data-id="'.$row['id'].'">delete</button>';

$('#delbtn').click( function () {

        if ( $('tr.selected').hasClass('selected') ) {
            var id = $('td button[type=button]').attr('data-id');
            var data = {'id': id };

             alert(id);

                    // $.ajax({...