Google Tag Manager Theme Functions for WordPress

google-tag-manager.php

<?php
/**
 * drunkenux-theme functions and definitions
 *
 * Utility functions for the site
 *
 * @package Drunken UX
 * @subpackage drunkenux-theme
 * @since Drunken UX Theme 2.0
 *
 * TABLE OF CONTENTS
 *  1. VARIABLES
 *  2. GTM Functions
 *  3. ACTION HOOKS
 */
 
// ***** VARIABLES *****

define('GTM_ID', 'GTM-########');

// ***** GTM FUNCTIONS *****

// Output iframe noscript GTM include
function action_add_gtm_body() {
  echo '<!-- Google Tag Manager (noscript) -->
<noscript><iframe src="https://www.googletagmanager.com/ns.html?id=' . GTM_ID . '"
height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>
<!-- End Google Tag Manager (noscript) -->';
}

// Output script GTM include
function action_add_gtm_head() {
  echo "<!-- Google Tag Manager -->
<script>
  window.dataLayer = window.dataLayer || [];
  (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
  new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
  j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
  'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
})(window,document,'script','dataLayer','" . GTM_ID . "');
</script>
<!-- End Google Tag Manager -->";
}


// ***** ACTION HOOKS *****

add_action( 'wp_body_open', '\action_add_gtm_body' );
add_action( 'wp_head', '\action_add_gtm_head' );