# DataTables example Child rows with StateSave

The DataTables API has a number of methods for attaching child rows to a parent row in the DataTable. This can be used to show additional information about a row, useful for cases where you wish to convey more information about a row than there is space for in the host table.

The example below makes use of both `stateSave` and the `row().child` methods to first check if a row is already displayed, and if so hide it (`row().child.hide()`), otherwise show it (`row().child.show()`). The content of the child row in this example is defined by the `format()` function, but you would replace that with whatever content you wanted to show, possibly including, for example, an Ajax call to the server to obtain any extra information.

Because of the state save element it is possible to maintain the state for this example across reloads. The user must add a listener for the `requestChild.dt` to display the row in whatever format that they please.

The listeners must also be set before the table initialisation, otherwise when a state is attempting to load, the functionality set in the listeners will not be available.

| Name | Position | Office | Salary
--- | --- | --- | --- | ---
| Name | Position | Office | Salary

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

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

`// Formatting function for row details - modify as you need function format(d) { // `d` is the original data object for the row return ( '<dl>' + '<dt>Full name:</dt>' + '<dd>' + d.name + '</dd>' + '<dt>Extension number:</dt>' + '<dd>' + d.extn + '</dd>' + '<dt>Extra info:</dt>' + '<dd>And any further details here (images etc)...</dd>' + '</dl>' ); } var table = $('#example').DataTable({ ajax: '../ajax/data/objects.txt', columns: [ { className: 'dt-control', orderable: false, data: null, defaultContent: '' }, { data: 'name' }, { data: 'position' }, { data: 'office' }, { data: 'salary' } ], order: [[1, 'asc']], rowId: 'id', stateSave: true }); table.on('requestChild.dt', function (e, row) { row.child(format(row.data())).show(); }); // Add event listener for opening and closing details $('#example').on('click', 'tbody td.dt-control', function () { var tr = $(this).closest('tr'); var row = table.row(tr); if (row.child.isShown()) { // This row is already open - close it row.child.hide(); } else { // Open this row row.child(format(row.data())).show(); } });`
`// Formatting function for row details - modify as you need function format(d) { // `d` is the original data object for the row return ( '<dl>' + '<dt>Full name:</dt>' + '<dd>' + d.name + '</dd>' + '<dt>Extension number:</dt>' + '<dd>' + d.extn + '</dd>' + '<dt>Extra info:</dt>' + '<dd>And any further details here (images etc)...</dd>' + '</dl>' ); } let table = new DataTable('#example', { ajax: '../ajax/data/objects.txt', columns: [ { className: 'dt-control', orderable: false, data: null, defaultContent: '' }, { data: 'name' }, { data: 'position' }, { data: 'office' }, { data: 'salary' } ], order: [[1, 'asc']], rowId: 'id', stateSave: true }); table.on('requestChild.dt', function (e, row) { row.child(format(row.data())).show(); }); // Add event listener for opening and closing details table.on('click', 'tbody td.dt-control', function (e) { let tr = e.target.closest('tr'); let row = table.row(tr); if (row.child.isShown()) { // This row is already open - close it row.child.hide(); } else { // Open this row row.child(format(row.data())).show(); } });`

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.