is_customize_preview() – Function | Developer.WordPress.org

Whether the site is being previewed in the Customizer.

Return

bool True if the site is being previewed in the Customizer, false otherwise.

function is_customize_preview() {
	global $wp_customize;

	return ( $wp_customize instanceof WP_Customize_Manager ) && $wp_customize->is_preview();
}

Used by	Description
WP_Widget_Text::render_control_template_scripts()`wp-includes/widgets/class-wp-widget-text.php`	Renders form template scripts.
wp_custom_css_cb()`wp-includes/theme.php`	Renders the Custom CSS style element.
get_custom_header_markup()`wp-includes/theme.php`	Retrieves the markup for a custom header.
the_custom_header_markup()`wp-includes/theme.php`	Prints the markup for a custom header.
get_custom_logo()`wp-includes/general-template.php`	Returns a custom logo, linked to home unless the theme supports removing the link on the home page.
WP_Customize_Selective_Refresh::handle_render_partials_request()`wp-includes/customize/class-wp-customize-selective-refresh.php`	Handles the Ajax request to return the rendered partials for the requested placements.
wp_admin_bar_customize_menu()`wp-includes/admin-bar.php`	Adds the “Customize” link to the Toolbar.
wp_site_icon()`wp-includes/general-template.php`	Displays site icon meta tags.
_custom_background_cb()`wp-includes/theme.php`	Default custom background callback.
WP_Widget_Recent_Comments::__construct()`wp-includes/widgets/class-wp-widget-recent-comments.php`	Sets up a new Recent Comments widget instance.
_wp_menu_item_classes_by_context()`wp-includes/nav-menu-template.php`	Adds the class property classes for the current context, if applicable.

Version	Description
4.0.0	Introduced.