Version 4 supported
This version of Silverstripe CMS is still supported though will not receive any additional features. Go to documentation for the most recent stable version.

Rich-text editing (WYSIWYG)

Editing and formatting content is the bread and butter of every content management system, which is why Silverstripe CMS has a tight integration with our preferred editor library, TinyMCE.

On top of the base functionality, we use our own insertion dialogs to ensure you can effectively select and upload files. In addition to the markup managed by TinyMCE, we use shortcodes to store information about inserted images or media elements.

The framework comes with a HTMLEditorField form field class which encapsulates most of the required functionality. It is usually added through the DataObject::getCMSFields() method:


use SilverStripe\Forms\FieldList;
use SilverStripe\Forms\HTMLEditor\HTMLEditorField;
use SilverStripe\ORM\DataObject;

class MyObject extends DataObject 
    private static $db = [
        'Content' => 'HTMLText'
    public function getCMSFields() 
        return new FieldList(
            new HTMLEditorField('Content')

Specify which configuration to use

By default, a config named 'cms' is used in any new HTMLEditorField.

If you have created your own HtmlEditorConfig and would like to use it, you can call HtmlEditorConfig::set_active('myConfig') and all subsequently created HTMLEditorField will use the configuration with the name 'myConfig'.

You can also specify which HtmlEditorConfig to use on a per field basis via the construct argument. This is particularly useful if you need different configurations for multiple HTMLEditorField on the same page or form.

use SilverStripe\Forms\FieldList;
use SilverStripe\Forms\HTMLEditor\HTMLEditorField;
use SilverStripe\ORM\DataObject;

class MyObject extends DataObject 
    private static $db = [
        'Content' => 'HTMLText',
        'OtherContent' => 'HTMLText'
    public function getCMSFields() 
        return new FieldList([
            new HTMLEditorField('Content'),
            new HTMLEditorField('OtherContent', 'Other content', $this->OtherContent, 'myConfig')

In the above example, the 'Content' field will use the default 'cms' config while 'OtherContent' will be using 'myConfig'.


To keep the JavaScript editor configuration manageable and extensible, we've wrapped it in a PHP class called HtmlEditorConfig. The class comes with its own defaults, which are extended through the Configuration API in the framework (and the cms module in case you've got that installed).

There can be multiple configs, which should always be created / accessed using HtmlEditorConfig::get(). You can then set the currently active config using set_active().

Currently the order in which the _config.php files are executed depends on the module directory names. Execution order is alphabetical, so if you set a TinyMCE option in the aardvark/_config.php, this will be overridden in vendor/silverstripe/framework/admin/_config.php and your modification will disappear.

Adding and removing capabilities

In its simplest form, the configuration of the editor includes adding and removing buttons and plugins.

You can add plugins to the editor using the Framework's HtmlEditorConfig::enablePlugins() method. This will transparently generate the relevant underlying TinyMCE code.


use SilverStripe\Forms\HTMLEditor\HtmlEditorConfig;

This utilities the TinyMCE's PluginManager::load function under the hood (check the TinyMCE documentation on plugin loading for details).

Plugins and advanced themes can provide additional buttons that can be added (or removed) through the configuration. Here is an example of adding a ssmacron button after the charmap button:


HtmlEditorConfig::get('cms')->insertButtonsAfter('charmap', 'ssmacron');

Buttons can also be removed:


HtmlEditorConfig::get('cms')->removeButtons('tablecontrols', 'blockquote', 'hr');
Internally HtmlEditorConfig uses the TinyMCE's theme_advanced_buttons option to configure these. See the TinyMCE documentation of this option for more details.

Setting options

TinyMCE behaviour can be affected through its configuration options. These options will be passed straight to the editor.

One example of the usage of this capability is to redefine the TinyMCE's whitelist of HTML tags - the tags that will not be stripped from the HTML source by the editor.


// Add start and type attributes for <ol>, add <object> and <embed> with all attributes.
    'img[class|src|alt|title|hspace|vspace|width|height|align|onmouseover|onmouseout|name|usemap],' .
    'iframe[src|name|width|height|title|align|allowfullscreen|frameborder|marginwidth|marginheight|scrolling],' .
    'object[classid|codebase|width|height|data|type],' .
    'embed[src|type|pluginspage|width|height|autoplay],' .
    'param[name|value],' .
    'map[class|name|id],' .
    'area[shape|coords|href|target|alt],' .
The default setting for the CMS's extended_valid_elements we are overriding here can be found in vendor/silverstripe/admin/_config.php.

Writing custom plugins

It is also possible to add custom plugins to TinyMCE, for example toolbar buttons. You can enable them through HtmlEditorConfig::enablePlugins():


HtmlEditorConfig::get('cms')->enablePlugins(['myplugin' => '../../../app/javascript/myplugin/editor_plugin.js']);

You can learn how to create a plugin from the TinyMCE documentation.

Image and media insertion

The HtmlEditorField API also handles inserting images and media files into the managed HTML content. It can be used both for referencing files on the webserver filesystem (through the File and Image APIs), as well as hotlinking files from the web.

We use shortcodes to store information about inserted images or media elements. The ShortcodeParser API post-processes the HTML content on rendering, and replaces the shortcodes accordingly. It also takes care of care of placing the shortcode replacements relative to its surrounding markup (e.g. left/right alignment).

Image size pre-sets

Silverstripe CMS will suggest pre-set image size in the HTMLEditor. Editors can quickly switch between the pre-set size when interacting with images in the HTMLEditorField.

The default values are "Best fit" (600 pixels width) and original size. Developers can customise the pre-set sizes by altering their HTMLEditorConfig.

You can alter the defaults for all HTMLEditor in your YML configuration.

    - name: widesize
      i18n: SilverStripe\Forms\HTMLEditor\TinyMCEConfig.WIDE_SIZE
      text: Wide size
      width: 900

You can edit the image size pre-sets for an individual configuration with this code snippet.

use SilverStripe\Forms\HTMLEditor\HtmlEditorConfig;
use SilverStripe\Forms\HTMLEditor\TinyMCEConfig;

HtmlEditorConfig::get('cms')->setOption('image_size_presets', [
        'width' => 300,
        'text' => 'Small fit',
        'name' => 'smallfit',
        'default' => true
        'width' => 600,
        'i18n' =>  TinyMCEConfig::class . '.BEST_FIT',
        'text' => 'Best fit',
        'name' => 'bestfit'
        'i18n' =>  TinyMCEConfig::class . '.ORIGINAL_SIZE',
        'text' => 'Original size',
        'name' => 'originalsize'

oEmbed: Embedding media through external services

The "oEmbed" standard is implemented by many media services around the web, allowing easy representation of files just by referencing a website URL. For example, a content author can insert a playable youtube video just by knowing its URL, as opposed to dealing with manual HTML code.

oEmbed powers the "Insert from web" feature available through HtmlEditorField. Internally this service is provided by the embed library.

To disable oembed you will need to follow the below to remove the plugin from tinymce, as well as disabling the internal service via yml:

Name: oembed-disable
  enabled: false

Use the following config if you need to send outbound requests through a proxy:

Name: myembed
After: coreoembed
      - proxy: '111.222.333.444:55'

Limiting oembed URLs

HtmlEditorField can have whitelists set on both the scheme (default http & https) and domains allowed when inserting files for use with oembed.

This is performed through the config variables on the RemoteFileFormFactory class:

Name: oembed-restrictions
    - https
    - http
    - ftp
    - localhost
    - 80
    - 443
    - 23

This allows a white or blacklist to be applied to schema, domain, or port (if provided). Note that both blacklist and whitelist need to match, and are only ignored if the rules are empty for any of the above values.

By default live sites (SS_ENVIRONMENT_TYPE="live") will not attempt to resolve oembed urls that point to localhost to protect your site from cross site request forgery.


Since TinyMCE generates markup, it needs to know which doctype your documents will be rendered in. You can set this through the element_format configuration variable. It defaults to the stricter 'xhtml' setting, for example rendering self closing tags like <br/> instead of <br>.

In case you want to adhere to HTML4 instead, use the following configuration:

HtmlEditorConfig::get('cms')->setOption('element_format', 'html');

By default, TinyMCE and Silverstripe CMS will generate valid HTML5 markup, but it will strip out HTML5 tags like <article> or <figure>. If you plan to use those, add them to the valid_elements configuration setting.

Also, the HTMLValue API underpinning the HTML processing parses the markup into a temporary object tree which can be traversed and modified before saving. The built-in parser only supports HTML4 and XHTML syntax. In order to successfully process HTML5 tags, please use the 'silverstripe/html5' module.


Customising the "Insert" panels

In the standard installation, you can insert links (internal/external/anchor/email), images as well as flash media files. The forms used for preparing the new content element are rendered by Silverstripe CMS, but there's some JavaScript involved to transfer back and forth between a content representation the editor can understand, present and save.

Example: Remove field for "image captions"

use SilverStripe\Core\Extension;

// File: app/src/MyToolbarExtension.php
class MyToolbarExtension extends Extension 
    public function updateFieldsForImage(&$fields, $url, $file) 
// File: app/_config.php
use SilverStripe\Admin\ModalController;


Adding functionality is a bit more advanced, you'll most likely need to add some fields to the PHP forms, as well as write some JavaScript to ensure the values from those fields make it into the content elements (and back out in case an existing element gets edited). There's lots of extension points in the ModalController class to get you started.

Security groups with their own editor configuration

Different groups of authors can be assigned their own config, e.g. a more restricted rule set for content reviewers (see the "Security" ) The config is available on each user record through Member::getHtmlEditorConfigForCMS(). The group assignment is done through the "Security" interface for each Group record. Note: The dropdown is only available if more than one config exists.

Using the editor outside of the CMS

Each interface can have multiple fields of this type, each with their own toolbar to set formatting and insert HTML elements. They do share one common set of dialogs for inserting links and other media though, encapsulated in the ModalController class. In the CMS, those dialogs are automatically instantiate, but in your own interfaces outside of the CMS you have to take care of instantiate yourself:

use SilverStripe\Admin\ModalController;
use SilverStripe\Control\Controller;

// File: app/src/MyController.php
class MyObjectController extends Controller 
    public function Modals() 
        return ModalController::create($this, "Modals");

Note: The dialogs rely on CMS-access, e.g. for uploading and browsing files, so this is considered advanced usage of the field.

// File: app/_config.php
HtmlEditorConfig::get('cms')->removeButtons('sslink', 'ssmedia');
HtmlEditorConfig::get('cms')->addButtonsToLine(2, 'link', 'media');

Developing a wrapper to use a different WYSIWYG editors with HTMLEditorField

WYSIWYG editors are complex beasts, so replacing it completely is a difficult task. The framework provides a wrapper implementation for the basic required functionality, mainly around selecting and inserting content into the editor view. Have a look in HtmlEditorField.js and the ss.editorWrapper object to get you started on your own editor wrapper. Note that the HtmlEditorConfig is currently hardwired to support TinyMCE, so its up to you to either convert existing configuration as applicable, or start your own configuration.