Can't delete the default jQuery in the theme

Question

In my theme, jQuery is loaded in the header by default. I even dequed it in my functions.php but still in the header I have the jquery :

function remove_jquery_migrate( &$scripts){
    if(!is_admin()){
        $scripts->remove( 'jquery');
        $scripts->add( 'jquery', false, array( 'jquery-core' ), '1.2.1' );
    }
}
add_filter( 'wp_default_scripts', 'remove_jquery_migrate' );

function wpdocs_dequeue_script() {
    wp_dequeue_script( 'jquery' );
}
add_action( 'wp_print_scripts', 'wpdocs_dequeue_script', 100 );

but this is printed in the header:

<script type='text/javascript' src='...wp-includes/js/jquery/jquery.js?ver=1.12.4'></script>

I don't know if a plugin is causing this but I want to remove this as I am already loading the jquery using Google CDN in the footer.

Answer 1

An example on how to deregister a WordPress built-in library and load your own:

function load_custom_scripts() {
    wp_deregister_script( 'jquery' );
    wp_register_script('jquery', '//code.jquery.com/jquery-2.2.4.min.js', array(), '2.2.4', true); // true will place script in the footer
    wp_enqueue_script( 'jquery' );
}
if(!is_admin()) {
    add_action('wp_enqueue_scripts', 'load_custom_scripts', 99);
}

Answer 2

First of all: is your Google jquery enqueued properly? If you just dump the script link in the footer, WP won't know jquery is loaded and plugins that need it will enqueue it regardless of whether you dequeued it in your theme.

Secondly, are you sure you are enqueueing the right jquery version? If you enqueue an older version of jquery, a smart plugin might detect that and enqueue a later version to make itself work.