I couldn’t add defer tag in plugin javascripts. Google developer pagespeed test suggests me to add defer tag in contact form 7 javascripts.
This is how contact form 7 includes javascript in header.
add_action( 'wp_enqueue_scripts', 'wpcf7_enqueue_scripts' );
function wpcf7_enqueue_scripts() {
// jquery.form.js originally bundled with WordPress is out of date and deprecated
// so we need to deregister it and re-register the latest one
wp_deregister_script( 'jquery-form' );
wp_register_script( 'jquery-form', wpcf7_plugin_url( 'jquery.form.js' ),
array( 'jquery' ), '2.52', true );
$in_footer = true;
if ( 'header' === WPCF7_LOAD_JS )
$in_footer = false;
wp_enqueue_script( 'contact-form-7', wpcf7_plugin_url( 'scripts.js' ),
array( 'jquery', 'jquery-form' ), WPCF7_VERSION, $in_footer );
do_action( 'wpcf7_enqueue_scripts' );
}
Now how to add defer=”defer” tag in the above code?
As of WordPress 4.1 there is a filter:
script_loader_tag
. You can use it to find the correct script:Old answer
There is no dedicated filter available ⦠at least I cannot see one. But â¦
wp_print_scripts()
callsWP_Scripts->do_items()
WP_Scripts->do_item()
esc_url()
'clean_url'
.And here we go:
Caveat: not tested, just an idea. 🙂
Update
I have written and tested a plugin with this code.