MENU – show class in wp_list_pages for links that have kids

This comes in handy if you are using a list_page menu and need to change the style of menu elements that have children, liks add an arrow. This needs to be in the functions file.

add_filter('page_css_class', 'nice_navigation_page_css_class', 10, 2);
/**
 * adds class "page-has-children" to all pages that have children
 * @param array $class.    The page css class being modified, passed as an array from Walker_Page
 * @param object $page.    The page object passed from Walker_Page
 * @return array            Returns the new page css class.
 */
function nice_navigation_page_css_class($class, $page) {
 // check if current page has children
 $children = get_pages('child_of='.$page->ID);
 if (sizeof($children) > 0) {
  $class[] = "page-has-children";
 }
 
 return $class;
}