load jquery in footer not working

Question

Ok, i've tried all day long and do not know, how this can be. I have a website on which i load jquery like that:

function my_script_loader() {
if (!is_admin()) { // only load for front end
    //Clear jQuery if already registered
    wp_deregister_script('jquery');
    wp_register_script('jquery', "http" . ($_SERVER['SERVER_PORT'] == 443 ? "s" : "") . "://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js", array(), '1.11.1', '',true);
    wp_enqueue_script('jquery');
    } // End of if statement
} // End of Function
add_action('wp_enqueue_scripts', 'my_script_loader');

The expected result in the Dom is:

<script type="text/javascript" defer="defer" src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js">

Then i am doing the exact same thing on another website which is a subdomain:

function script_loader() {
if (!is_admin()) {
    //Clear jQuery if already registered
    wp_deregister_script('jquery');
    wp_register_script('jquery', "http" . ($_SERVER['SERVER_PORT'] == 443 ? "s" : "") . "://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js", array() , '1.12.4', '',true);
    wp_enqueue_script('jquery');
    }
} // End of Function
add_action('wp_enqueue_scripts', 'script_loader');

The unexpected result in the Dom is:

<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js?ver=1.12.4">

I have disabled plugins and removed all scripts but the script is not deferred. How can that happen? Thanks for your interest. theo

Answer 1

As Mark Kaplun said in the comments, something is adding defer to your one domain's script.

If you want your subdomain jQuery script to also have defer, this should do it:

function my_add_defer ($tag, $handle, $src) {
    if ($handle == 'jquery') {
        return str_replace (' src=', ' defer="defer" src=', $tag);
    }
    return $tag;
}
add_filter ('script_loader_tag', 'my_add_defer', 10, 3);

Answer 2

This is the one, that caused the difference and that i was missing:

function defer_parsing_of_js ( $url ) {
if ( FALSE === strpos( $url, '.js' ) ) return $url;

return "$url' defer='defer";
  }
add_filter( 'clean_url', 'defer_parsing_of_js', 11, 1 );