Lazy-Loading Update

Since lazy-loading images via the native loading attribute was proposed for addition to WordPress core, there have been quite a few updates. With the WordPress 5.4 releaseRelease A release is the distribution of the final version of an application. A software release may be either public or private and generally constitutes the initial or new generation of a new or upgraded application. A release is preceded by the distribution of alpha and then beta versions of the software. cycle entering betaBeta A pre-release of software that is given out to a large group of users to trial under real conditions. Beta versions have gone through alpha testing in-house and are generally fairly close in look, feel and function to the final product; however, design changes often occur as part of the process. almost two weeks ago, there was too little time for testing the feature plugin and creating a proper coreCore Core is the set of software required to run WordPress. The Core Development Team builds WordPress. patchpatch A special text file that describes changes to code, by identifying the files and lines which are added, removed, and altered. It may also be referred to as a diff. A patch can be applied to a codebase for testing.. The feature is now aimed at being released as part of WordPress 5.5, to be merged early in the release cycle to get further testing while fully integrated with the platform. This post is a follow-up to the original announcement, providing information about the latest updates.

Standardization of the loading attribute

The WHATWG spec pull-request for adding the loading attribute to img elements with possible values “eager” and “lazy” was recently merged, so it is now part of the HTMLHTML HyperText Markup Language. The semantic scripting language primarily used for outputting content in web browsers. Living Standard (see general paragraph about lazy loading attributes and more specific information about the img loading attribute). This was a requirement for WordPress to ship with support for the feature. While it was unclear whether this was going to happen in time for the WordPress 5.4 release (which it now has), the 5.5 timeline certainly works for it, as now the feature can be merged way ahead of the initial beta.

Browser support

At the time of this publication, Chrome (76+), Edge (79+) and Opera (64+) already support the loading attribute. Firefox support was merged recently, and is intended to land in version 75. WebKit support is actively being worked on, so seeing the feature land in Safari is also on the horizon. We will monitor how browser vendors are adopting the standard, but with recent developments it looks promising. All major browsers will support the loading attribute by the time WordPress 5.5 is released (currently 2020/08/11). Please refer to for current updates.

State of the feature pluginFeature Plugin A plugin that was created with the intention of eventually being proposed for inclusion in WordPress Core. See Features as Plugins.

The feature plugin for lazy-loading images in WordPress core (GitHub repository) is in a good state to be used already. The exact implementation is undergoing some changes, mainly focused on optimizing the mechanism to add the loading attribute to images in post content for performance by combining it with the existing regular expression in core that adds srcset and sizes attributes. These changes will likely affect the new APIs outlined in the original post, and a dev notedev note Each important change in WordPress Core is documented in a developers note, (usually called dev note). Good dev notes generally include: a description of the change; the decision that led to this change a description of how developers are supposed to work with that change. Dev notes are published on Make/Core blog during the beta phase of WordPress release cycle. Publishing dev notes is particularly important when plugin/theme authors and WordPress developers need to be aware of those changes.In general, all dev notes are compiled into a Field Guide at the beginning of the release candidate phase. about the definite state will be published closer to the WordPress 5.5 release.

The pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the Plugin Directory or can be cost-based plugin from a third-party is ready to be widely tested. It has already undergone some testing, but we are looking for more testers! We will also like to receive any type of feedback on the implementation.