Is subpage function

is-subpage-function

function is_subpage($pid) {      // $pid = The ID of the page we're looking for pages underneath
    global $post;         // load details about this page
    if(is_page()&&($post->post_parent==$pid||is_page($pid))) 
           return true;   // we're at the page or at a sub page
    else 
           return false;  // we're elsewhere
}