optimize GTM preloading

Author: jekuer

assets/css/style.css

@@ -3,7 +3,7 @@
  * PHP Microsite Boilerplate
  * +++++++++++++++++++++++++
  * 
- * Version: 2.0.4
+ * Version: 2.0.5
  * Creator: Jens Kuerschner (https://jenskuerschner.de)
  * Project: https://github.com/jekuer/php-microsite-boilerplate
  * License: GNU General Public License v3.0	(gpl-3.0)

config.php

@@ -6,7 +6,7 @@
 
 // Current version of the website.
 // Will be used to control css and js caching.
-$version_nr = '2.0.4';
+$version_nr = '2.0.5';
 
 // Multilanguage
 $language['default'] = 'en'; // Use a key from the array below.

index.php

@@ -5,7 +5,7 @@
  * PHP Microsite Boilerplate
  * +++++++++++++++++++++++++
  * 
- * Version: 2.0.4
+ * Version: 2.0.5
  * Creator: Jens Kuerschner (https://jenskuerschner.de)
  * Project: https://github.com/jekuer/php-microsite-boilerplate
  * License: GNU General Public License v3.0	(gpl-3.0)

package.json

@@ -1,6 +1,6 @@
 {
   "name": "php-microsite-boilerplate",
-  "version": "2.0.4",
+  "version": "2.0.5",
   "description": "An extremely simple and lightweight PHP framework/boilerplate to spin-up microsites at high speed. Optimized for Performance, Security, SEO, and Directus CMS.",
   "keywords": [
     "css",

templates/header.php

@@ -30,7 +30,11 @@
     <?php include_once './templates/general_meta.php'; ?>
 
     <!-- Preconnect to other servers/domains -->
-    <link rel="preconnect" href="https:///www.googletagmanager.com" crossorigin>
+    <?php
+    if ($the_gtm_id != '') {
+      echo '<link rel="preconnect" href="https:///www.googletagmanager.com" crossorigin>';
+    }
+    ?>
 
     <!-- Preload fonts (optional, only .woff2 recommended) -->
     <link rel="preload" href="./assets/fonts/open-sans-v17-latin-regular.woff2" as="font" type="font/woff2" crossorigin>