How to delay JavaScript in WordPress

How to delay non critical (external) JavaScript in WordPress. Load and execute non-critical scripts only on user interaction.

I often see external JavaScript that is non critical and with long loading times in the waterfall, slowing down the website. Mostly it is code for Google analytics, Tag Manager, Facebook pixel or Google AdSense.

We can use two plugins to delay non critical JavaScript in WordPress, Paid and free:

Perfmatters

Perfmatters is my favourite performance plugin, because it has a lot of features to speed optimize a WordPress website that a caching plugin does not do. In Perfmatters we have the option to delay JavaScripts.

You can find the options under: Options / Assets / JavaScript

Read this article how to delay JavaScript in Perfmatters

Flying Scripts

You can also use a free plugin called “Flying Scripts” to achieve this. It is also supported in “Flying Press” a caching plugin.

List of common files to delay

Below is a list of common JavaScript files you can delay.

Google Analytics

ga( '
ga('
google-analytics.com/analytics.js

Local Perfmatters gtag.js v4

gtagv4.js

Google Tag Manager

/gtm.js
/gtag/js
gtag(
/gtm-

Google AdSense

adsbygoogle.js

Facebook Pixel

fbevents.js
fbq(
/busting/facebook-tracking/

Facebook customer chat

xfbml.customerchat.js

Google reCAPTCHA

grecaptcha.execute

Google Optimize

optimize.js

Hotjar

static.hotjar.com/c/hotjar-

TikTok Analytics

analytics.tiktok.com/i18n/pixel/events.js

Specific Plugins (Only Used When They Load Below The Fold)

/wp-content/plugins/plugin-name/

WooCommerce Cart Fragments

cart-fragments.min.js

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