There are built in conditional WordPress functions for testing for a page:
if ( is_page(2) ) {
// stuff
}
Or for testing if a page is a child of a certain page:
if ( $post->post_parent == '2' ) {
// stuff
}
But there is no built in function that combines these two things, which is a fairly common need. For example, loading a special CSS page for a whole "branch" of content. Like a "videos" page and all its children individual videos pages.
This function (add to functions.php file) creates new logical function to be used in this way:
function is_tree($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
};
Usage
if (is_tree(2)) {
// stuff
}
