Wordpress: Is Child Function

gistfile1.aw

/*
* Checks if the page is the parent or a child of the page matching the $pid param
* $pid can be the page slug or the page ID #
*
* This function is best used to display menus when the parent/top level menu item needs
* a rollover state or special treatment.
*
* @param \$pid (string or int)
* returns true if current page ID matches $pid, else return false
*/


function is_child( \$pid ) {  // $pid = The ID of the page we're looking for pages underneath
        global \$post;        // load details about this page

    // if \$pid is an ID
        if (is_int(\$pid)) {

                if ( is_page(\$pid) )
                        return true;
            // get the page's children if the ID of a child matches the $pid return true
                \$anc = get_post_ancestors( \$post->ID );
                foreach ( \$anc as \$ancestor ) {
                        if( is_page() && \$ancestor == \$pid ) {
                                return true;
                        }
                }
        }
    // if $pid is a page slug
        elseif (is_string(\$pid)) {
                // Get page by 'SLUG'
                \$page = get_page_by_path( \$pid );
                if (\$post->ID == \$page->ID) {
                        return true;
                }

                \$anc = get_post_ancestors( \$post->ID );
                foreach ( \$anc as \$ancestor ) {
                        if( is_page() && $ancestor == \$page->ID ) {
                                return true;
                        }
                }
        }

        return false;  // we arn't at the page, and the page is not an ancestor
}

/*
Used in a template:

<img src="home<?php if (is_child(0)){?>-ro<?php } ?>.jpg">
or
<img src="home<?php if (is_child('home')){?>-ro<?php } ?>.jpg">

if true equals
<img src="home-ro.jpg">


*/