Displays a navigation menu.

Signature

wp_nav_menu( $args = array() )
args
 (array) Optional. Array of nav menu arguments.
Default: array()

Return

(mixed) Menu output if $echo is false, false if there are no items or no menu was found.

Source

function wp_nav_menu( $args = array() ) {
	static $menu_id_slugs = array();

	$defaults = array( 'menu' => '', 'container' => 'div', 'container_class' => '', 'container_id' => '', 'menu_class' => 'menu', 'menu_id' => '',
	'echo' => true, 'fallback_cb' => 'wp_page_menu', 'before' => '', 'after' => '', 'link_before' => '', 'link_after' => '', 'items_wrap' => '<ul id="%1$s" class="%2$s">%3$s</ul>',
	'depth' => 0, 'walker' => '', 'theme_location' => '' );

	$args = wp_parse_args( $args, $defaults );
	/**
	 * Filter the arguments used to display a navigation menu.
	 *
	 * @since 3.0.0
	 *
	 * @see wp_nav_menu()
	 *
	 * @param array $args Array of wp_nav_menu() arguments.
	 */
	$args = apply_filters( 'wp_nav_menu_args', $args );
	$args = (object) $args;

182 more lines...
WP Trac GitHub

Link here