# DataTables example Index column

Highly-interactive tables often require a 'counter' column that contains the position for each row in the table. This column should not be sortable, and will change dynamically as the ordering and searching applied to the table is altered by the end user.

This example shows how this can be achieved with DataTables, where the first column is the counter column, and the cells are updated whenever the table is drawn to show their index location in the current filtering set. Only the rows that are displayed are updated to help improve performance in large data sets.

This is done by using `on` to add a `draw` event handler when the table starts up and then `column().nodes()` is used to get all of the -tag td`elements and`-api every()` to loop over them an update the display.

Note that since this is applied only to the displayed cells, we need to take account of the paging offset, which is done with the `start` property from `page.info()`.

| Name | Position | Office | Age | Salary
--- | --- | --- | --- | --- | ---
| Tiger Nixon | System Architect | Edinburgh | 61 | $320,800
| Garrett Winters | Accountant | Tokyo | 63 | $170,750
| Ashton Cox | Junior Technical Author | San Francisco | 66 | $86,000
| Cedric Kelly | Senior JavaScript Developer | Edinburgh | 22 | $433,060
| Airi Satou | Accountant | Tokyo | 33 | $162,700
| Brielle Williamson | Integration Specialist | New York | 61 | $372,000
| Herrod Chandler | Sales Assistant | San Francisco | 59 | $137,500
| Rhona Davidson | Integration Specialist | Tokyo | 55 | $327,900
| Colleen Hurst | JavaScript Developer | San Francisco | 39 | $205,500
| Sonya Frost | Software Engineer | Edinburgh | 23 | $103,600
| Jena Gaines | Office Manager | London | 30 | $90,560
| Quinn Flynn | Support Lead | Edinburgh | 22 | $342,000
| Charde Marshall | Regional Director | San Francisco | 36 | $470,600
| Haley Kennedy | Senior Marketing Designer | London | 43 | $313,500
| Tatyana Fitzpatrick | Regional Director | London | 19 | $385,750
| Michael Silva | Marketing Designer | London | 66 | $198,500
| Paul Byrd | Chief Financial Officer (CFO) | New York | 64 | $725,000
| Gloria Little | Systems Administrator | New York | 59 | $237,500
| Bradley Greer | Software Engineer | London | 41 | $132,000
| Dai Rios | Personnel Lead | Edinburgh | 35 | $217,500
| Jenette Caldwell | Development Lead | New York | 30 | $345,000
| Yuri Berry | Chief Marketing Officer (CMO) | New York | 40 | $675,000
| Caesar Vance | Pre-Sales Support | New York | 21 | $106,450
| Doris Wilder | Sales Assistant | Sydney | 23 | $85,600
| Angelica Ramos | Chief Executive Officer (CEO) | London | 47 | $1,200,000
| Gavin Joyce | Developer | Edinburgh | 42 | $92,575
| Jennifer Chang | Regional Director | Singapore | 28 | $357,650
| Brenden Wagner | Software Engineer | San Francisco | 28 | $206,850
| Fiona Green | Chief Operating Officer (COO) | San Francisco | 48 | $850,000
| Shou Itou | Regional Marketing | Tokyo | 20 | $163,000
| Michelle House | Integration Specialist | Sydney | 37 | $95,400
| Suki Burks | Developer | London | 53 | $114,500
| Prescott Bartlett | Technical Author | London | 27 | $145,000
| Gavin Cortez | Team Leader | San Francisco | 22 | $235,500
| Martena Mccray | Post-Sales support | Edinburgh | 46 | $324,050
| Unity Butler | Marketing Designer | San Francisco | 47 | $85,675
| Howard Hatfield | Office Manager | San Francisco | 51 | $164,500
| Hope Fuentes | Secretary | San Francisco | 41 | $109,850
| Vivian Harrell | Financial Controller | San Francisco | 62 | $452,500
| Timothy Mooney | Office Manager | London | 37 | $136,200
| Jackson Bradshaw | Director | New York | 65 | $645,750
| Olivia Liang | Support Engineer | Singapore | 64 | $234,500
| Bruno Nash | Software Engineer | London | 38 | $163,500
| Sakura Yamamoto | Support Engineer | Tokyo | 37 | $139,575
| Thor Walton | Developer | New York | 61 | $98,540
| Finn Camacho | Support Engineer | San Francisco | 47 | $87,500
| Serge Baldwin | Data Coordinator | Singapore | 64 | $138,575
| Zenaida Frank | Software Engineer | New York | 63 | $125,250
| Zorita Serrano | Software Engineer | San Francisco | 56 | $115,000
| Jennifer Acosta | Junior JavaScript Developer | Edinburgh | 43 | $75,650
| Cara Stevens | Sales Assistant | New York | 46 | $145,600
| Hermione Butler | Regional Director | London | 47 | $356,250
| Lael Greer | Systems Administrator | London | 21 | $103,500
| Jonas Alexander | Developer | San Francisco | 30 | $86,500
| Shad Decker | Regional Director | Edinburgh | 51 | $183,000
| Michael Bruce | JavaScript Developer | Singapore | 29 | $183,000
| Donna Snider | Customer Support | New York | 27 | $112,000
| Name | Position | Office | Age | Salary

- JavaScript
- HTML
- CSS
- Ajax
- Server-side script

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

`var table = $('#example').DataTable({ columnDefs: [ { searchable: false, orderable: false, targets: 0 } ], order: [[1, 'asc']], on: { draw: function (e) { let start = e.dt.page.info().start; e.dt.column(0, {page: 'current'}) .nodes() .each(function (cell, i) { cell.textContent = start + i + 1; }); } } });`
`const table = new DataTable('#example', { columnDefs: [ { searchable: false, orderable: false, targets: 0 } ], order: [[1, 'asc']], on: { draw: (e) => { let start = e.dt.page.info().start; e.dt.column(0, {page: 'current'}) .nodes() .each((cell, i) => { cell.textContent = start + i + 1; }); } } });`

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

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:

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.