Ajax Datatable initialization bootstrap 3

<script type="text/javascript" language="javascript" >
 $(document).ready(function(){
      var dataTable = $('#dtTable').DataTable({
           "processing":true,
           "serverSide":true,
           "order":[],
           "ajax":{
                url:"<?php echo base_url() . 'controller/query_db'; ?>",
                type:"POST"
           },
           "columnDefs":[{
                     "targets":[0, 3, 4],
                     "orderable":false,
                },
           ],
           //lengthChange: true,
           "dom": '<"pull-left"B><"pull-left"l><"pull-right"f>tp',
           buttons: [{
                text: 'New Category',
                action: function ( e, dt, node, config ){
                location.href = 'category/cat_crud';
                }
            },
            'excel', 'colvis'
        ],
        lengthMenu: [ [10, 25, 50, -1], [10, 25, 50, "All"] ],

      });
      table.buttons().container()
        .appendTo( '#dtTable_wrapper .col-sm-6:eq(0)');
        //dropdown

 });
 </script>