I'm using the code below to do the following task:

If page id is 22834 load a specific facebook pixel script with "Purchased" track event, else (all other pages) load the facebook pixel script with "PageView" track event.

Current code:

function wpb_hook_javascript() {
  if (is_page ('22834')) { 
    ?>
        <script>!function(f,b,e,v,n,t,s)
        {if(f.fbq)return;n=f.fbq=function(){n.callMethod?
        n.callMethod.apply(n,arguments):n.queue.push(arguments)};
        if(!f._fbq)f._fbq=n;n.push=n;n.loaded=!0;n.version='2.0';
        n.queue=[];t=b.createElement(e);t.async=!0;
        t.src=v;s=b.getElementsByTagName(e)[0];
        s.parentNode.insertBefore(t,s)}(window, document,'script',
        'https://connect.facebook.net/en_US/fbevents.js');
        fbq('init', 'XXXXXXXXXX');
        fbq('track', 'Purchase');</script><noscript><img height="1" width="1" style="display:none" src="https://www.facebook.com/tr?id=XXXXXXXXXX&ev=Purchase&noscript=1"></noscript>
    
<?php else ?>

        <script>!function(f,b,e,v,n,t,s)
        {if(f.fbq)return;n=f.fbq=function(){n.callMethod?
        n.callMethod.apply(n,arguments):n.queue.push(arguments)};
        if(!f._fbq)f._fbq=n;n.push=n;n.loaded=!0;n.version='2.0';
        n.queue=[];t=b.createElement(e);t.async=!0;
        t.src=v;s=b.getElementsByTagName(e)[0];
        s.parentNode.insertBefore(t,s)}(window, document,'script',
        'https://connect.facebook.net/en_US/fbevents.js');
        fbq('init', 'XXXXXXXXXX');
        fbq('track', 'PageView');</script><noscript><img height="1" width="1" style="display:none" src="https://www.facebook.com/tr?id=XXXXXXXXXX&ev=PageView&noscript=1"></noscript>

<?php
  }
}

add_action('wp_head', 'wpb_hook_javascript');

The script is working and applying the code correctly in my website, but with this code in my functions.php the wp-admin area it's showing this error:

There has been a critical error on your website. Please check your site admin email inbox for instructions.

If I remove the code the wp-admin works again!

CodePudding user response：

1. It's recommended to use wp_enqueue_scripts instead of using wp_head hook for outputing js and css.

2. You may need to use !is_admin() condition inside your function as well.

3. You're missing a closing } and opening { before and after your else statement.

function wpb_hook_javascript(){
    if (!is_admin() && is_page('22834')) {
    ?>
        <script>
            ! function(f, b, e, v, n, t, s) {
                if (f.fbq) return;
                n = f.fbq = function() {
                    n.callMethod ?
                        n.callMethod.apply(n, arguments) : n.queue.push(arguments)
                };
                if (!f._fbq) f._fbq = n;
                n.push = n;
                n.loaded = !0;
                n.version = '2.0';
                n.queue = [];
                t = b.createElement(e);
                t.async = !0;
                t.src = v;
                s = b.getElementsByTagName(e)[0];
                s.parentNode.insertBefore(t, s)
            }(window, document, 'script',
                'https://connect.facebook.net/en_US/fbevents.js');
            fbq('init', 'XXXXXXXXXX');
            fbq('track', 'Purchase');
        </script><noscript><img height="1" width="1" style="display:none" src="https://www.facebook.com/tr?id=XXXXXXXXXX&ev=Purchase&noscript=1"></noscript>

    <?php } else { ?>

        <script>
            ! function(f, b, e, v, n, t, s) {
                if (f.fbq) return;
                n = f.fbq = function() {
                    n.callMethod ?
                        n.callMethod.apply(n, arguments) : n.queue.push(arguments)
                };
                if (!f._fbq) f._fbq = n;
                n.push = n;
                n.loaded = !0;
                n.version = '2.0';
                n.queue = [];
                t = b.createElement(e);
                t.async = !0;
                t.src = v;
                s = b.getElementsByTagName(e)[0];
                s.parentNode.insertBefore(t, s)
            }(window, document, 'script',
                'https://connect.facebook.net/en_US/fbevents.js');
            fbq('init', 'XXXXXXXXXX');
            fbq('track', 'PageView');
        </script><noscript><img height="1" width="1" style="display:none" src="https://www.facebook.com/tr?id=XXXXXXXXXX&ev=PageView&noscript=1"></noscript>

<?php
    }
}

add_action('wp_head', 'wpb_hook_javascript');