Get jQuery version in WordPress via PHP - php

Question

I'm not sure if this is possible but I was hoping that I could retrieve WordPress' built-in jQuery version number programmatically via PHP.
I prefer to include a CDN version of jQuery using wp_register_script(), then I use the WordPress' built-in jQuery as a fallback.
The problem with using a CDN version is that if WordPress updates their built-in version of jquery, the CDN version might not match. So I was hoping to fetch the version number (maybe using wp_default_scripts()), and then pass that through to wp_register_script().
Any ideas on how I get do this?

Answer 1

I borrowed from WP jQuery Plus:
function hs_script_enqueuer() {
if( !is_admin() ) {
// Enqueue so we can grab the built-in version
wp_enqueue_script( 'jquery' );
// Get jquery handle - WP 3.6 or newer changed the jQuery handle (once we're on 3.6+ we can remove this logic)
$jquery_handle = (version_compare($wp_version, '3.6-alpha1', '>=') ) ? 'jquery-core' : 'jquery';
// Get the WP built-in version
$wp_jquery_ver = $GLOBALS['wp_scripts']->registered[$jquery_handle]->ver;
// Just in case it doesn't work, add a fallback version
$jquery_ver = ( $wp_jquery_ver == '' ) ? '1.8.3' : $wp_jquery_ver;
// De-register built-in jquery
wp_deregister_script('jquery');
// Register CDN version
wp_register_script( 'jquery', '//ajax.googleapis.com/ajax/libs/jquery/'. $jquery_ver .'/jquery.min.js' );
// Enqueue new jquery
wp_enqueue_script( 'jquery' );
}
}
add_action( 'wp_enqueue_scripts', 'hs_script_enqueuer' );
// Add jquery fallback if CDN is unavailable
function jquery_fallback() {
echo '<script>window.jQuery || document.write(\'<script src="' . includes_url( 'js/jquery/jquery.js' ) . '"><\/script>\')</script>' . "\n";
}
add_action( 'wp_head', 'jquery_fallback' );

Answer 2

if( ! function_exists('register_jquery_script') ){
function register_jquery_script(){
/* Get jquery handle - WP 3.6 or newer changed the jQuery handle (once we're on 3.6+ we can remove this logic) */
$jquery_handle = (version_compare($wp_version, '3.6-alpha1', '>=') ) ? 'jquery-core' : 'jquery';
/* Get the WP built-in version */
$wp_jquery_ver = $GLOBALS['wp_scripts']->registered[$jquery_handle]->ver;
/* Just in case it doesn't work, add a fallback version */
$jquery_ver = ( $wp_jquery_ver == '' ) ? '1.8.3' : $wp_jquery_ver;
/* the URL to check CDN accessibility */
$url = 'http://ajax.googleapis.com/ajax/libs/jquery/' . $jquery_ver . '/jquery.min.js';
/* test CDN accessibility */
$test_url = wp_remote_fopen($url);
/* deregisters the default WordPress jQuery */
wp_enqueue_script( 'jquery' );
wp_deregister_script( 'jquery' );
/* if CDN available - load it */
if( $test_url !== false ) {
wp_register_script( 'jquery', '//ajax.googleapis.com/ajax/libs/jquery/'. $jquery_ver .'/jquery.min.js', false , false , true );
}
/* if CDN unavailable - load local jquery copy */
else{
wp_register_script('jquery', get_template_directory_uri() . '/js/jquery.min.js', __FILE__, false, false, true);
}
wp_enqueue_script('jquery');
}
add_action('wp_enqueue_scripts','register_jquery_script');
}
you must be sure that you loaded local jquery into the template_directory/js/ with name jquery.min.js
I'm loading all scripts in wp_footer() by default for page loading performance.
If you loading your js scripts in wp_header(), you will change the last true to false on lines:
wp_register_script( 'jquery' , $src , false , false , false );
Enjoy it!