JavaScript clean up

- Modernizr is now enqueued and included after stylesheets

- jQuery is no longer hardcoded since WP now supports protocol-relative
URLs

- jQuery fallback output is handled by a new function in lib/scripts.php
(the method is still the same one from HTML5 Boilerplate)

doc/lib.md

@@ -87,8 +87,8 @@ If you're using LESS, make sure you compile the files to the proper locations:
 
 JavaScript is loaded in the following order:
 
-1. `/theme/assets/js/vendor/modernizr-2.6.2.min.js` (in `head.php`)
+1. `/theme/assets/js/vendor/modernizr-2.6.2.min.js`
-2. `jquery-1.9.0.min.js` via Google CDN with local fallback (in `head.php`)
+2. `jquery-1.9.0.min.js` via Google CDN with local fallback
 3. `/theme/assets/js/plugins.js`
 4. `/theme/assets/js/main.js`
 

lib/scripts.php

@@ -9,8 +9,8 @@
  * 4. /child-theme/style.css (if a child theme is activated)
  *
  * Enqueue scripts in the following order:
- * 1. /theme/assets/js/vendor/modernizr-2.6.2.min.js  (in head.php)
+ * 1. /theme/assets/js/vendor/modernizr-2.6.2.min.js
- * 2. jquery-1.9.0.min.js via Google CDN              (in head.php)
+ * 2. jquery-1.9.0.min.js via Google CDN
  * 3. /theme/assets/js/plugins.js
  * 4. /theme/assets/js/main.js
  */
@@ -26,21 +26,44 @@ function roots_scripts() {
   }
 
   // jQuery is loaded in header.php using the same method from HTML5 Boilerplate:
-  // Grab Google CDN's jQuery, with a protocol relative URL; fall back to local if offline
+  // Grab Google CDN's latest jQuery with a protocol relative URL; fall back to local if offline
   // It's kept in the header instead of footer to avoid conflicts with plugins.
   if (!is_admin()) {
     wp_deregister_script('jquery');
-    wp_register_script('jquery', '', '', '1.9.0', false);
+    wp_register_script('jquery', '//ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js', array('modernizr'), null, false);
   }
 
   if (is_single() && comments_open() && get_option('thread_comments')) {
     wp_enqueue_script('comment-reply');
   }
 
+  wp_register_script('modernizr', get_template_directory_uri() . '/assets/js/vendor/modernizr-2.6.2.min.js', false, null, false);
   wp_register_script('roots_plugins', get_template_directory_uri() . '/assets/js/plugins.js', false, null, false);
   wp_register_script('roots_main', get_template_directory_uri() . '/assets/js/main.js', false, null, false);
+  wp_enqueue_script('modernizr');
+  wp_enqueue_script('jquery');
   wp_enqueue_script('roots_plugins');
   wp_enqueue_script('roots_main');
 }
 
 add_action('wp_enqueue_scripts', 'roots_scripts', 100);
+
+// http://wordpress.stackexchange.com/a/12450
+function roots_jquery_local_fallback($src, $handle) {
+  static $add_jquery_fallback = false;
+
+  if ($add_jquery_fallback) {
+    echo '<script>window.jQuery || document.write(\'<script src="' . get_template_directory_uri() . '/assets/js/vendor/jquery-1.9.0.min.js"><\/script>\')</script>' . "\n";
+    $add_jquery_fallback = false;
+  }
+
+  if ($handle === 'jquery') {
+    $add_jquery_fallback = true;
+  }
+
+  return $src;
+}
+
+if (!is_admin()) {
+  add_filter('script_loader_src', 'roots_jquery_local_fallback', 10, 2);
+}

templates/head.php

@@ -8,11 +8,6 @@
   <title><?php wp_title('|', true, 'right'); bloginfo('name'); ?></title>
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
 
-  <script src="<?php echo get_template_directory_uri(); ?>/assets/js/vendor/modernizr-2.6.2.min.js"></script>
-
-  <script src="//ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js"></script>
-  <script>window.jQuery || document.write('<script src="<?php echo get_template_directory_uri(); ?>/assets/js/vendor/jquery-1.9.0.min.js"><\/script>')</script>
-
   <?php wp_head(); ?>
 
   <link rel="alternate" type="application/rss+xml" title="<?php echo get_bloginfo('name'); ?> Feed" href="<?php echo home_url(); ?>/feed/">