# DataTables example Row selection

When you want to have user selectable rows in DataTables, it is relatively trivial when using DOM based data - but when using server-side processing, DataTables doesn't retain DOM row elements over pages / filtering etc. As such, you will need to keep a track of which rows a user as selected and mark them as selected on each draw.

This is shown in this demo, which uses a unique ID assigned to the TR element (this is done automatically through the use of the `DT_RowId` special property returned as part of the object given by the server for each row) to track which rows are selected and reselect them is appropriate on a draw.

Name | Position | Office | Extn. | Start date | Salary
--- | --- | --- | --- | --- | ---
Name | Position | Office | Extn. | Start date | Salary

- Javascript
- HTML
- CSS
- Ajax
- Server-side script

The Javascript shown below is used to initialise the table shown in this example:

`$(document).ready(function() { var selected = []; $("#example").dataTable({ "processing": true, "serverSide": true, "ajax": "scripts/ids-arrays.php", "rowCallback": function( row, data, displayIndex ) { if ( $.inArray(data.DT_RowId, selected) !== -1 ) { $(row).addClass('selected'); } } }); $('#example tbody').on('click', 'tr', function () { var id = this.id; var index = $.inArray(id, selected); if ( index === -1 ) { selected.push( id ); } else { selected.splice( index, 1 ); } $(this).toggleClass('selected'); } ); } );`

In addition to the above code, the following Javascript library files are loaded for use in this example:

- ../../media/js/jquery.js
- ../../media/js/jquery.dataTables.js

The HTML shown below is the raw HTML table element, before it has been enhanced by DataTables:

This example uses a little bit of additional CSS beyond what is loaded from the library files (below), in order to correctly display the table. The additional CSS used is shown below:

``

The following CSS library files are loaded for use in this example to provide the styling of the table:

- ../../media/css/jquery.dataTables.css

This table loads data by Ajax. The latest data that has been loaded is shown below. This data will update automatically as any additional data is loaded.

The script used to perform the server-side processing for this table is shown below. Please note that this is just an example script using PHP. Server-side processing scripts can be written in any language, using the protocol described in the DataTables documentation.