How can we add page length button with dom:(my code is in description)

ramji15788

$('.wpcl #list-table').DataTable( {
'pageLength':15,
colReorder: true,
stateSave: true,
dom: 'Blfrtip',
buttons: [
{
extend: 'copy',
text: wpcl_script_vars.copybtn,
},
{
extend: 'print',
title: productTitle,
text: wpcl_script_vars.printbtn,
customize: function ( win ) {
$(win.document.body)
.css( 'background-color', '#fff' )
.css( 'padding', '1px' );

            $(win.document.body).find( 'table' )
                .addClass( 'compact' )
                .css( 'font-size', 'inherit' )
                .css( 'border', '0px' )
                .css( 'border-collapse', 'collapse' );

            $(win.document.body).find( 'table th' )
                .css( 'padding', '5px 8px 8px' )
                .css( 'background-color', '#f1f1f1' )
                .css( 'border-bottom', '0px' );

            $(win.document.body).find( 'table td' )
                .css( 'border', '1px solid #dfdfdf' )
                .css( 'padding', '8px' );

            $(win.document.body).find( 'table tr:nth-child(even)' )
                .css( 'background-color', '#f9f9f9' );
        }
    },
    {
        extend: 'excelHtml5',
        title: fileName
    },
    {
        extend: 'csvHtml5',
        title: fileName
    },
    {
        extend: 'pdfHtml5',
        title: productTitle,
        orientation: pdfOrientation,
        pageSize: pdfPageSize,
        filename: fileName,
        customize: function(doc)
        {
            doc.styles.tableHeader.fillColor = '#f1f1f1';
            doc.styles.tableHeader.color = '#000';
            doc.styles.tableBodyEven.fillColor = '#f9f9f9';
            doc.styles.tableBodyOdd.fillColor = '#fff';
        }
    },
    ],
    pagingType: 'full',
    scrollX: true,
    language: {
        'search': wpcl_script_vars.search,
        'emptyTable': wpcl_script_vars.emptyTable,
        'zeroRecords': wpcl_script_vars.zeroRecords,
        'tableinfo': wpcl_script_vars.tableinfo,
        'lengthMenu': wpcl_script_vars.lengthMenu,
        paginate: {
            first:    '«',
            previous: '‹',
            next:     '›',
            last:     '»'
        },
        buttons: {
        copyTitle: wpcl_script_vars.copyTitle,
        copySuccess: {
            _: wpcl_script_vars.copySuccessMultiple,
            1: wpcl_script_vars.copySuccessSingle,
        }
    },
    aria: {
        paginate: {
            first:    wpcl_script_vars.paginateFirst,
            previous: wpcl_script_vars.paginatePrevious,
            next:     wpcl_script_vars.paginateNext,
            last:     wpcl_script_vars.paginateLast,
        }
    }
}
} );