content-experiment-js-api-client

/**
 * Add GA Content Experiments Scripts Here
 */
function content_experiments_head_script() {
    
    // Replace '2' with the post/page ID of the original version of the page you are testing
    if(is_page(2)) { ?>

        <!-- Load the Content Experiment JavaScript API client for the experiment -->
        <script src="//www.google-analytics.com/cx/api.js?experiment=YOUR_EXPERIMENT_ID"></script>

        <script>
          // Ask Google Analytics which variation to show the user.
          var chosenVariation = cxApi.chooseVariation();
        </script>

    <?php }

}

add_action( 'wp_head', 'content_experiments_head_script' );