Deferred script loading has been added to WordPress to improve site performance and page load times.
With the most recent WordPress update, version 6.4, many sites’ page load speeds and performance will be enhanced by changes to how scripts are loaded on the front end.
The performance of loading scripts using defer and async characteristics has been improved by the incorporation of script loading techniques into the core and packaged themes of WordPress.
The time it takes for a website to become interactive can be considerably sped up by using these properties to tell the browser to load scripts in the background (async) or after the rest of the page has loaded (defer).
Intelligent Script Handling for Quicker Page Loads
Before, JavaScript scripts contained in WordPress themes and plugins were loaded without having their asynchronous loading requirements specified. This meant that while they were being fetched and executed, they blocked other downloads and delayed page rendering.
Pages with WordPress content will load more quickly for website visitors after an upgrade, notably increasing the CWV’s first contentful paint (FCP) metric, which influences how quickly the page initially loads.
How This Was Achieved using WordPress in the Background
When ‘defer’ is enqueued, it is added to JavaScript files for blocks from WordPress.com such as navigation menus and embedded media. Defer is now used by the wp-embed script to show embedded content.
The ability to add these features was not previously standardized. Developers now have a standardized method to manage when their scripts load thanks to the inclusion of a dedicated API in WordPress 6.3 and its full implementation in 6.4.
The most delayed scripts are also moved back into the area by the upgrade because they are no longer rendering-blocking. This enhances performance by enabling the browser to find and cache them early.
Effects In The Real World For Website Visitors
Pages with WordPress content will load more quickly for website visitors following an update. After the page loads up, there will be less “jank” or page element moving.
