To add a custom hash to the end of each URL added through the menu backend is easier said than done.
You could build a custom walker.
Or you could try to hook in the walker_nav_menu_start_el
filter and edit just that, perhaps like so[nav-menu-template.php]:
add_filter( 'walker_nav_menu_start_el', 'my_skip_to_nav', 10, 4 );
function my_skip_to_nav( $item_output, $item, $depth, $args ){
$indent = ( $depth ) ? str_repeat( "\t", $depth ) : '';
$class_names = $value = '';
$classes = empty( $item->classes ) ? array() : (array) $item->classes;
$classes[] = 'menu-item-' . $item->ID;
$class_names = join( ' ', apply_filters( 'nav_menu_css_class', array_filter( $classes ), $item, $args ) );
$class_names = $class_names ? ' class="' . esc_attr( $class_names ) . '"' : '';
$id = apply_filters( 'nav_menu_item_id', 'menu-item-'. $item->ID, $item, $args );
$id = $id ? ' id="' . esc_attr( $id ) . '"' : '';
$output .= $indent . '<li' . $id . $value . $class_names .'>';
$attributes = ! empty( $item->attr_title ) ? ' title="' . esc_attr( $item->attr_title ) .'"' : '';
$attributes .= ! empty( $item->target ) ? ' target="' . esc_attr( $item->target ) .'"' : '';
$attributes .= ! empty( $item->xfn ) ? ' rel="' . esc_attr( $item->xfn ) .'"' : '';
// Here happens the magic!
$attributes .= ! empty( $item->url ) ? ' href="' . esc_attr( $item->url ) .'#navigation"' : '';
$item_output = $args->before;
$item_output .= '<a'. $attributes .'>';
$item_output .= $args->link_before . apply_filters( 'the_title', $item->title, $item->ID ) . $args->link_after;
$item_output .= '</a>';
$item_output .= $args->after;
return $item_output;
}
Then again, you perhaps don't want something this complicated, and you can have much simpler solutions using Javascript/jQuery.
Javascript solution
Use jQuery to add your anchor to the navigation links
jQuery(document).ready(function($){
$('#navigation a').each(function(){
$(this).attr('href', $(this).attr('href') + '#navigation');
});
});
#navigation
at the end of your links absolutely does what you are looking for, given that your navigation menu has anid
ofnavigation
.