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register_sidebar ›

register_sidebar ( $args = array() )
  • (array|string) $args { Optional. Array or string of arguments for the sidebar being registered.
    Required: No
    Default: array()
  • (string) Sidebar ID added to $wp_registered_sidebars global.
Defined at:

Builds the definition for a single sidebar and returns the ID.

Accepts either a string or an array and then parses that against a set of default arguments for the new sidebar. WordPress will automatically generate a sidebar ID and name based on the current number of registered sidebars if those arguments are not included.

When allowing for automatic generation of the name and ID parameters, keep in mind that the incrementor for your sidebar can change over time depending on what other plugins and themes are installed.

If theme support for 'widgets' has not yet been added when this function is called, it will be automatically enabled through the use of add_theme_support()


function register_sidebar( $args = array() ) {
	global $wp_registered_sidebars;

	$i = count( $wp_registered_sidebars ) + 1;

	$id_is_empty = empty( $args['id'] );

	$defaults = array(
		/* translators: %d: Sidebar number. */
		'name'          => sprintf( __( 'Sidebar %d' ), $i ),
		'id'            => "sidebar-$i",
		'description'   => '',
		'class'         => '',
		'before_widget' => '<li id="%1$s" class="widget %2$s">',
		'after_widget'  => "</li>\n",
		'before_title'  => '<h2 class="widgettitle">',
		'after_title'   => "</h2>\n",

	 * Filters the sidebar default arguments.
	 * @since 5.3.0
	 * @see register_sidebar()
	 * @param array $defaults The default sidebar arguments.
	$sidebar = wp_parse_args( $args, apply_filters( 'register_sidebar_defaults', $defaults ) );

	if ( $id_is_empty ) {
				/* translators: 1: The 'id' argument, 2: Sidebar name, 3: Recommended 'id' value. */
				__( 'No %1$s was set in the arguments array for the "%2$s" sidebar. Defaulting to "%3$s". Manually set the %1$s to "%3$s" to silence this notice and keep existing sidebar content.' ),

	$wp_registered_sidebars[ $sidebar['id'] ] = $sidebar;

	add_theme_support( 'widgets' );

	 * Fires once a sidebar has been registered.
	 * @since 3.0.0
	 * @param array $sidebar Parsed arguments for the registered sidebar.
	do_action( 'register_sidebar', $sidebar );

	return $sidebar['id'];