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function is not described

Walker_Nav_Menu::start_lvl() WP 3.0.0

Starts the list before the elements are added.

This is a method of the class: Walker_Nav_Menu

Hooks from the method
Return

Null. Nothing.

Usage

$Walker_Nav_Menu = new Walker_Nav_Menu();
$var = $Walker_Nav_Menu->start_lvl( $output, $depth, $args );
$output(string) (required) (passed by reference — &)
Used to append additional content (passed by reference).
$depth(int)
Depth of menu item. Used for padding.
Default: 0
$args(stdClass)
An object of wp_nav_menu() arguments.
Default: null

Notes

  • See: Walker::start_lvl()

Changelog

Since 3.0.0 Introduced.

Code of Walker Nav Menu::start lvl: wp-includes/class-walker-nav-menu.php WP 5.4.2

<?php
public function start_lvl( &$output, $depth = 0, $args = null ) {
	if ( isset( $args->item_spacing ) && 'discard' === $args->item_spacing ) {
		$t = '';
		$n = '';
	} else {
		$t = "\t";
		$n = "\n";
	}
	$indent = str_repeat( $t, $depth );

	// Default class.
	$classes = array( 'sub-menu' );

	/**
	 * Filters the CSS class(es) applied to a menu list element.
	 *
	 * @since 4.8.0
	 *
	 * @param string[] $classes Array of the CSS classes that are applied to the menu `<ul>` element.
	 * @param stdClass $args    An object of `wp_nav_menu()` arguments.
	 * @param int      $depth   Depth of menu item. Used for padding.
	 */
	$class_names = join( ' ', apply_filters( 'nav_menu_submenu_css_class', $classes, $args, $depth ) );
	$class_names = $class_names ? ' class="' . esc_attr( $class_names ) . '"' : '';

	$output .= "{$n}{$indent}<ul$class_names>{$n}";
}