Advanced Custom Fields to work.
It enables you to add tracking and retargeting code to individual posts and pages. * Version: 0.3 * Author: Online Mastery Limited * Author URI: http://onlinemastery.co.uk * License: GPL2 */ add_action('plugins_loaded', 'retargeting_load_fields'); function retargeting_load_fields() { if(function_exists('register_field_group') && current_user_can('manage_options')) { register_field_group(array ( 'id' => 'acf_unique-tracking-code', 'title' => 'Unique Tracking Code', 'fields' => array ( array ( 'key' => 'field_5434ce24932a8', 'label' => 'Enter your Retargeting or Tracking code in the box below', 'name' => '_unique_tracking_code', 'type' => 'textarea', 'default_value' => '', 'placeholder' => 'Add Tracking code here ...', 'prepend' => '', 'append' => '', 'formatting' => 'html', 'maxlength' => '', ), ), 'location' => array ( array ( array ( 'param' => 'post_type', 'operator' => '==', 'value' => 'post', 'order_no' => 0, 'group_no' => 0, ), ), array ( array ( 'param' => 'post_type', 'operator' => '==', 'value' => 'page', 'order_no' => 0, 'group_no' => 1, ), ), ), 'options' => array ( 'position' => 'normal', 'layout' => 'default', 'hide_on_screen' => array ( ), ), 'menu_order' => 1, )); } } function unique_tracking_code_add_head_script() { if ( ! is_admin() && function_exists('the_field')) { the_field('_unique_tracking_code'); } } add_action( 'wp_head', 'unique_tracking_code_add_head_script' );