Datatable

//Datatable Refresh
$('.dataTables').DataTable().ajax.reload();
// or
$('#example-select').on('change', function(){
    $('#example').DataTable().ajax.reload(); 
});


//Destroy the old datatable
$('.dataTables').dataTable().fnDestroy();

//Passiing data dynamically to datatable
$('#btn-search').click(function() {
    $userID   = $('#inputUserID').val();
    $activity = $('#inputActivity').val();
    $dtFrom   = $('#inputStartDate').val();
    $dtTo     = $('#inputEndDate').val();
     
    dataTable.ajax.data = function(d) {
        d.userID   = $userID;
        d.activity = $activity;
        d.dtFrom   = $dtFrom;
        d.dtTo     = $dtTo;
    };
 
    dataTable.ajax.reload(); //Datatable Reinitialization/Refresh/reload
});

In above process, we can also set dynamic message like this

message: function () {
   return 'Hello world';
}


//Dynamically Title adding during Print
buttons: [
  {
    extend: 'print',
    text: 'All',
    title: function () { return $('#dt-title').val(); },
  }
]


//Set the first column's title with columnDefs option:

$('#example').dataTable( {
  "columnDefs": [
    { "title": "My column title", "targets": 0 }
  ]
} );

//OR, using columns option: 

$('#example').dataTable( {
  "columns": [
    { "title": "My column title" },
    null,
    null,
    null,
    null
  ]
} );

//hiding columns by this command:
fnSetColumnVis( 1, false );
Where first parameter is index of column and second parameter is visibility.

//hiding subset of columns by this command:
"dom": 'lfrtip',
    "columnDefs" : [          
        { "targets": [4,5], "visible": false }
     ]

//How to make DataTables subset of columns toggling
   var oTable = $('#example').DataTable({
       "dom": 'lfrtip',
       "columnDefs" : [          
           { "targets": [4,5], "visible": false }
        ]
   });

   $('a.column-toggle').on('click', function(e){
       var column = oTable.column($(this).data('id'));
       column.visible(!column.visible());
       e.preventDefault();
   });
   
Html:
http://jsfiddle.net/tmbua7sb/2/

// dir: SortDirection;
// $requestData['order'][0]['column'] is index of a column
// $requestData['order'][0]['dir'] is 'asc' or 'desc'
// $requestData['length'] is length: 5 that is number of records that will be shown simply limit 5
// $requestData['start'] is start: 0 that is offset or starting point of selecting records
// $requestData['search']['value'] is what will be search by using search box

Example:
$limit = $requestData['length']; // limit
$start = $requestData['start']; // offset
$orderable_col = $sortable_cols[$requestData['order'][0]['column']]; //column
$dir = $requestData['order'][0]['dir']; // asc/desc
$search = requestData['search']['value']; // a search string