Wordpress Enqueue Jquery From Google CDN

jquery-google-cdn.php

<?php
// Enqueue jQuery from Google CDN. Uses the currently registered WordPress jQuery version.
function google_jquery_enqueue() { 
	
	// Probably not necessary if called with the 'wp_enqueue_scripts' action.
	if (is_admin()) return; 
	global $wp_scripts; 
	
	// Change  this flag to have the CDN script triggered by wp_footer instead of wp_head.
	$cdn_script_in_footer = false;
	   
	//Register jQuery from Google CDN.
	if (is_a( $wp_scripts, 'WP_Scripts' ) && isset($wp_scripts->registered['jquery'])) {
		   
		// The WordPress jQuery version. 
		$registered_jquery_version = $wp_scripts -> registered[jquery] -> ver;
		if($registered_jquery_version) {
			  
			// The jQuery Google CDN URL. Makes a check for HTTP on top of SSL/TLS (HTTPS) to make sure the URL is correct.
			$google_jquery_url = ( $_SERVER['SERVER_PORT'] == 443 ? "https" : "http") . 
			"://ajax.googleapis.com/ajax/libs/jquery/$registered_jquery_version/jquery.min.js";
	 
			// Get the HTTP header response for the this URL, and check that its ok. If ok, include jQuery from Google CDN. 
			if(200 === wp_remote_retrieve_response_code(wp_remote_head( $google_jquery_url ))) {
			wp_deregister_script( 'jquery' );
			wp_register_script( 'jquery', $google_jquery_url , false, null, $cdn_script_in_footer );
			}
		}
	}
	/* 
	Enqueue jQuery from Google if available. Fall back to the local WordPress default.
	If the local WordPress jQuery is called, it will get included in the header no 
	matter what the $cdn_script_in_footer flag is set to.
	*/
	wp_enqueue_script( 'jquery' ); 
}
 
add_action( 'wp_enqueue_scripts', 'google_jquery_enqueue', 11 );