Before setting out on any coding adventure, I always outline what I want to do, how I might do it, and how I’ll know if it works.

At this point my needs are simple:

• Add a GA global tag to the site head.
• Present users with a way to opt-out of GA for my site.
• Display this option on the Privacy Policy page  (Admin > Settings > Privacy).

For this I’m going to try using:

• wp_head to add the Google scripts – one for tracking + one for opt-out.
• get_option to find the Privacy Policy page and conditionally add the opt-out script.
• A [shortcode] for placing the opt-out link anyewhere needed.

I’ll know it works if:

• The GA global tag script appears on all site pages.
• The GA opt-out script loads only on the Privacy Page.
• Clicking the opt-out link triggers a visible alert.
• Clicking the opt-out link adds the ga-disable cookie for the current device and browser.

In the USA, there are several ways to opt out of Google Analytics:

• Don’t use sites running Analytics – which is pretty much every site, so not a feasible option.
• Manually manage cookies via web browser settings – not hard, but not convenient either.
• Install the official Google Analytics Opt-Out Browser Add-On – this allows you to opt out of tracking on all sites, but I don’t suggest it.
• Opt-out for individual sites that provide a mechanism – what I’m doing here.

Child theme?

If you’re using a child theme, your custom code will always go there. If, like me, you’re using a completely custom theme, code can go directly in those files.

Files

While you can place this code in functions.php, I suggest creating a separate file that’s required by the theme. Mine is theme/inc/knotty-ga.php.

When you create a new GA property, the wizard  provides code for your site’s global tag.

Note that in GA, properties are also called accounts. Don’t confuse this with needing a separate Google account for each site / property – you don’t.

1. Sign in to your Google account.
2. Navigate to https://analytics.google.com/.
3. In the upper-right, click your user icon > Add Account (property).
4. Follow the on-screen steps.

For existing properties, you can regenerate the code by:

1. Sign in to Google and navigate to Analytics.
2. In the lower-left, click the Admin (gear) icon. A new page loads.
3. In the Property column, click Tracking Info > Tracking code.

This code adds the GA global tag to a site’s head. Use the example below by replacing all instances of UA-XXXXXXXXX-X with your site’s property ID.

Even better would be to replace the two inner JS tags with the block Google generates.

This code powers the opt-out link – it sets the ga-disable cookie and displays an on-screen alert.

Notice I’m using wp_head a second time. This could go with the previous example if it were needed on all pages. Here, I’m conditionally adding it to just the site’s Privacy page.

The opt-out can be displayed as a link:

<a href="javascript:gaOptout()">Opt out of Google Analytics for this site</a>

Or as a button:

<button onclick="gaOptout()">Opt out of Google Analytics for this site</button>

The problem is, you can’t enter either of these into the Visual or Text editors – the JS is stripped on save.

To solve this, I created a [ga_opt_out] shortcode:

I always test in a local or stage environment where I have FTP access should things go bad – I suggest you do too.

Once the updated theme files are in place, clear your caches, and check that:

• The GA global tag scripts are loading on every page.
• The GA opt-out script is loading on just the Privacy page.
• WP_DEBUG & dev tools show no errors.

Next, edit your Privacy page and insert the [ga_opt_out] shortcode where desired.

Next, view the Privacy page and click the opt-out link or button. An on-screen alert is displayed.

Finally, use your browser’s dev tool to check for the ga-disable cookie. In Chrome, click the Application tab > Storage: Cookies > Site name.

Whew – did it! I’m still new enough to WordPress theme development to be super excited when I accomplish this kind of thing. I document these adventures for my own benefit – if you’ve made it this far, thanks and I hope it helps you in some way!