Er zijn meerdere versies:
add_filter( ‘clean_url’, ‘defer_parsing_of_js’, 11, 1 ); // add async and defer to javascripts function wcs_defer_javascripts ( $url ) { if ( FALSE === strpos( $url, '.js' ) ) return $url; if ( strpos( $url, 'jquery.js' ) ) return $url; return "$url' async='async"; } add_filter( 'clean_url', 'wcs_defer_javascripts', 11, 1 );
Gevonden op: http://wpcodesnippet.com/add-async-and-defer-attributes-javascript-elements/
Na lang zoeken en uitproberen.
function defer_parsing_of_js ( $url ) {
if ( FALSE === strpos( $url, ‘.js’ ) ) return $url;
if ( strpos( $url, ‘jquery.js’ ) ) return $url;
return “$url’ defer=’defer”;
}
add_filter( ‘clean_url’, ‘defer_parsing_of_js’, 11, 1 );