dom->body->getElementsByTagName( 'amp-story-page' ); /** * The element * * @var DOMElement $page The element */ foreach ( $pages as $page ) { $page_nubmer++; $links = $page->getElementsByTagName( 'a' ); /** * The element * * @var DOMElement $link The element */ foreach ( $links as $link ) { $url = $link->getAttribute( 'href' ); $url = add_query_arg( [ 'utm_source' => "page_$page_nubmer" ], $url ); $link->setAttribute( 'href', $url ); } } } } } );