Attributes for Blocks

FAQ

How do I add an attribute?

In your selected block’s inspector controls (Block settings) scroll all the way to the bottom and click on “Advanced”. It should contain a section called “Additional attributes”.
Type an attribute name into the “Add attribute” field and press “Add” to add an attribute for the block. A new input with the attribute’s name should appear below, into which you can optionally insert the attribute value.
Example attributes: style, title, target, class, id, onclick, data-*, aria-*.

Why is the input disabled?

When the current user doesn’t have unfiltered_html capabilities attributes cannot be added and all existing attributes are stripped when the post is updated.

How does it work?

For regular blocks, attributes are added to the block save content’s root element, meaning they will be rendered only on the front end and not in the editor. For dynamic blocks the attributes are added via render_callback function and they may also be applied in the editor, depending if the block is rendered server or client side.

Does it work for every block?

It should work with normal blocks that render a valid WP Element that can utilize the blocks.getSaveContent.extraProps filter as well as dynamic blocks that utilize a render_callback. Third party blocks that do something unorthodox may not work.
Known unsupported blocks

Usage with Alpine.js

@ prefix in an attribute name is used for “override” mode in this plugin, for Alpine.js attributes use x-on:click instead of @click or use the shorthand syntax with two @ characters instead of one: @@click.

Disable block support

The afb_unsupported_blocks filter can be used in your child theme’s functions.php file to disable block support for adding additional attributes.

add_filter('afb_unsupported_blocks', function($blocks) {
    $blocks[] = 'core/button';
    return $blocks;
});

What happens when I disable this plugin?

Blocks with custom attributes may become invalid, depending on which attributes you’ve added. From there you can recover the block without the custom attributes by clicking “Attempt Block Recovery” or keep the block with custom attributes as HTML by choosing “Convert to HTML”. If you don’t want to risk blocks becoming invalid you need to remove all custom attributes before disabling the plugin.

How do I add unfiltered_html capability to user roles?

You can modify which roles have the unfiltered_html capability using custom code in your theme’s functions.php file or via a custom plugin. Only grant this capability if you trust the current and future users of that role to not do anything malicious.

add_action('init', function() {
    if($role = get_role('contributor')) {
        $role->add_cap('unfiltered_html');
    }
});