# Editor example Join tables - Cascading lists

Working with categories and sub-categories is a very common action in data intensive applications. It can be useful both for the programmer (i.e. you!) in terms of data manipulation and for the end user's conceptual model of the data. Categories are easy with Editor's `select` option - simply populate it with data and the end user can select from it. Sub-categories require a little more interaction since the options available depend on the value the user has selected for the main category.

This example demonstrates how Editor's `dependent()` method can be used to retrieve values for the `select` element based on the selection of another field. A blog post explains in detail how this example is constructed.

Name | Continent | Country
--- | --- | ---
Name | Continent | Country

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

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

`const editor = new DataTable.Editor({ ajax: '../php/cascadingLists.php', fields: [ { label: 'Name:', name: 'team.name' }, { label: 'Continent:', name: 'team.continent', type: 'select' }, { label: 'Country:', name: 'team.country', type: 'select' } ], table: '#example' }); editor.dependent('team.continent', '../php/countries.php'); new DataTable('#example', { ajax: { url: '../php/cascadingLists.php', type: 'POST' }, columns: [ { data: 'team.name' }, { data: 'continent.name' }, { data: 'country.name' } ], layout: { topStart: { buttons: [ { extend: 'create', editor: editor }, { extend: 'edit', editor: editor }, { extend: 'remove', editor: editor } ] } }, select: true });`

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.