将Facebook跟踪事件附加到Woocommerce中的订单接收页面

我想添加一个Facebook跟踪事件,其中包括购买金额和;货币到WooCommerce购买确认页面,无需借助插件。

<?php
/**
 * Append Facebook tracking Event
 */
add_action( 'woocommerce_thankyou', 'facebook_tracking_thank_you_page' );

function facebook_tracking_thank_you_page() {
    $currency = $order->get_order_currency();
    $total = $order->get_total();
echo ("<script>fbq('track', 'Purchase', {value: '<?php echo $total ?>',currency: '<?php echo $currency?>'});</script>");
}
?>

然而,这个脚本在确认页面上根本没有回应。它还会破坏页面的布局。

我现在已经尝试将echo语句添加到全局标头(包装在针对该特定页的if语句中):

<!-- Echo Facebook Tracking on Checkout -->
<?php
    global $post;
    if($post->post_type == 'page' && $post->ID == '3327'){
        echo "<script>fbq('track', 'Purchase', {value: '<?php echo $total ?>',currency: '<?php echo $currency?>'});</script>";
    }
?>

将其保存在functions.php文件中时:

/**
 * Append Facebook tracking Event
 */

add_action( 'woocommerce_thankyou', 'facebook_tracking_thank_you_page' );

function facebook_tracking_thank_you_page() {
    $currency = $order->get_order_currency();
    $total = $order->get_total();
}

但是,我在页面上看到的输出是:

<script>fbq('track', 'Purchase', {value: '<?php echo  ?>',currency: '<?php echo ?>'});</script>