remove li class & id for menu items and pages list

Question

Example of WordPress default CSS class output:

&l         


        

Answer 1

An addition to Richard's answer: We need to clean up the empty classes left behind:

//Strip Empty Classes
add_filter ('wp_nav_menu','strip_empty_classes');
function strip_empty_classes($menu) {
    $menu = preg_replace('/ class=(["\'])(?!active).*?\1/','',$menu);
    return $menu;
}