Wordpress - How to control what jQuery version to include, with wp_enqueue_script

I have developed a plugin for this specific problem. This plugin doesn't mess with WordPress jQuery as it is only loaded in the front-end. See: jQuery Manager for WordPress

Why yet another jQuery Updater / Manager / Developer / Debugging tool?

Because none of the developer tools lets you select a specific version of jQuery and/or jQuery Migrate. Providing both the production and the minified version. See features below!

✅ Only executed in the front-end, doesn't interfere with WordPress admin/backend and WP customizer (for compatibility reasons) See: https://core.trac.wordpress.org/ticket/45130 and https://core.trac.wordpress.org/ticket/37110

✅ Turn on/off jQuery and/or jQuery Migrate

✅ Activate a specific version of jQuery and/or jQuery Migrate

And much more! The code is open source, so you could study it, learn from it and contribute.

Almost everybody uses the incorrect handle

WordPress actually uses the jquery-core handle, not jquery:

https://github.com/WordPress/WordPress/blob/91da29d9afaa664eb84e1261ebb916b18a362aa9/wp-includes/script-loader.php#L226

// jQuery
$scripts->add( 'jquery', false, array( 'jquery-core', 'jquery-migrate' ), '1.12.4' );
$scripts->add( 'jquery-core', '/wp-includes/js/jquery/jquery.js', array(), '1.12.4' );
$scripts->add( 'jquery-migrate', "/wp-includes/js/jquery/jquery-migrate$suffix.js", array(), '1.4.1' );

The jquery handle is just an alias to load jquery-core with jquery-migrate

See more info about aliases: wp_register_script multiple identifiers?

The correct way to do it

In my example below I use the official jQuery CDN at https://code.jquery.com I also use script_loader_tag so that I could add some CDN attributes.
You could use the following code:

// Front-end not excuted in the wp admin and the wp customizer (for compatibility reasons)
// See: https://core.trac.wordpress.org/ticket/45130 and https://core.trac.wordpress.org/ticket/37110
function wp_jquery_manager_plugin_front_end_scripts() {
    $wp_admin = is_admin();
    $wp_customizer = is_customize_preview();

    // jQuery
    if ( $wp_admin || $wp_customizer ) {
        // echo 'We are in the WP Admin or in the WP Customizer';
        return;
    }
    else {
        // Deregister WP core jQuery, see https://github.com/Remzi1993/wp-jquery-manager/issues/2 and https://github.com/WordPress/WordPress/blob/91da29d9afaa664eb84e1261ebb916b18a362aa9/wp-includes/script-loader.php#L226
        wp_deregister_script( 'jquery' ); // the jquery handle is just an alias to load jquery-core with jquery-migrate
        // Deregister WP jQuery
        wp_deregister_script( 'jquery-core' );
        // Deregister WP jQuery Migrate
        wp_deregister_script( 'jquery-migrate' );

        // Register jQuery in the head
        wp_register_script( 'jquery-core', 'https://code.jquery.com/jquery-3.3.1.min.js', array(), null, false );

        /**
         * Register jquery using jquery-core as a dependency, so other scripts could use the jquery handle
         * see https://wordpress.stackexchange.com/questions/283828/wp-register-script-multiple-identifiers
         * We first register the script and afther that we enqueue it, see why:
         * https://wordpress.stackexchange.com/questions/82490/when-should-i-use-wp-register-script-with-wp-enqueue-script-vs-just-wp-enque
         * https://stackoverflow.com/questions/39653993/what-is-diffrence-between-wp-enqueue-script-and-wp-register-script
         */
        wp_register_script( 'jquery', false, array( 'jquery-core' ), null, false );
        wp_enqueue_script( 'jquery' );
    }
}
add_action( 'wp_enqueue_scripts', 'wp_jquery_manager_plugin_front_end_scripts' );


function add_jquery_attributes( $tag, $handle ) {
    if ( 'jquery-core' === $handle ) {
        return str_replace( "type='text/javascript'", "type='text/javascript' integrity='sha256-FgpCb/KJQlLNfOu91ta32o/NMZxltwRo8QtmkMRdAu8=' crossorigin='anonymous'", $tag );
    }
    return $tag;
}
add_filter( 'script_loader_tag', 'add_jquery_attributes', 10, 2 );

That's the size of the minified jQuery nowadays :)

You can load the latest from Google:

wp_deregister_script('jquery');
wp_register_script('jquery', ("http://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js"), false, '1.8.2');

Please keep in mind that this can cause issues moving forward, as you are forcing WordPress to load a certain version of jQuery instead of the version bundled with it. There are plugins out there that may be better suited for your needs, like WP JQuery Plus, which make sure to load the same version number as WordPress does, but with the benefit of loading it from Google.

Do not modify the version of jQuery enqueued by WordPress.

Just don't do it. Core depends on a specific version. Themes and Plugins depend on a certain version. That certain version is the version bundled with a given version of WordPress.

If you need to perform script minification, compression, or concatenation, you can certainly do that (you can roll your own, or use a Plugin, such as W3 Total Cache, to do it for you.)

But as you can see: if you're got a 46kB file, you're already dealing with some combination of minification and compression.