Reduce the JavaScript that blocks the page while it loads on WordPress

Why it matters

Total Blocking Time is a lab number that measures how long scripts keep the page from responding while it loads, and it is slightly above the threshold. Deferring scripts you do not need at once usually fixes it.

Staged change. Do this in stages and check each one before the next, so a mistake does not break your site or your mail.

The fix

1. List what loads on the slow page. A debugging plugin such as Query Monitor shows which plugin or theme adds each script. Deactivate or replace plugins that add heavy scripts on every page (sliders, popups, chat, social feeds, tracking add-ons).
2. Use an optimisation plugin to delay or defer scripts that are not needed straight away, and test the site after each change, since delaying a script that a menu or form needs breaks it.
3. Keep page builder pages light, with fewer nested sections and widgets, and use a lighter theme if the theme itself ships a lot of JavaScript.

Read the documentation ↗(opens in a new tab)

Related

• Reported by the Core Web Vitals check
• Make the largest element on the page load faster
• Make the largest element on the page load faster
• Stop the page layout from jumping while it loads
• Stop the page layout from jumping while it loads
• Make the page respond faster to clicks and taps
• Make the page respond faster to clicks and taps
• Reduce the JavaScript that blocks the page while it loads
• Collect real-user speed data for your site