The “first run” of the script loading optimization is in trunktrunk A directory in Subversion containing the latest development code in preparation for the next major release cycle. If you are running "trunk", then you are on the latest revision.. It uses both methods: splits the scripts queue in head and footer parts, then concatenates and compresses them before sending them to the browser. Most CSSCSS Cascading Style Sheets. is also concatenated and compressed.

There are two new constants that disable concatenating and compression: CONCATENATE_SCRIPTS and COMPRESS_SCRIPTS. Setting the first to false would disable both concatenating and compression, the second disables compression only. There is also a simple AJAX method to test if compressing from PHPPHP The web scripting language in which WordPress is primarily architected. WordPress requires PHP 7.4 or higher works as expected on the server. It is run only once and the result is saved as an option. It will run again if that option is deleted.

For 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 WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party. authors there are two new actions in the adminadmin (and super admin) footer: do_action('admin_print_footer_scripts'); and do_action("admin_footer-$hook_suffix");. The order of execution is:

1. "admin_footer" can be used to print scripts before the default footer scripts
2. "admin_print_footer_scripts" used to print the default scripts followed by any external scripts that were queued for the footer
3. "admin_footer-$hook_suffix" can be used to print scripts that should appear on a specific admin page only

The preferable way for plugins to add scripts to admin pages would be either to enqueue them properly (which is a must if the script depends on a default script) or to use the $hook_suffix hooksHooks In WordPress theme and development, hooks are functions that can be applied to an action or a Filter in WordPress. Actions are functions performed when a certain event occurs in WordPress. Filters allow you to modify certain functions. Arguments used to hook both filters and actions look the same. to add them only where needed.

New hook(s) may also be needed in the functions dealing with splitting or concatenating the script queue. Suggestions are welcome either here as comments or on tracTrac An open source project by Edgewall Software that serves as a bug tracker and project management tool for WordPress. as enhancements tickets.

Update: added do_action('admin_enqueue_scripts', $hook_suffix); allowing plugins to easily queue scripts on the exact pages. To find out the value for $hook_suffix on a specific page, echo it from your function and visit the page.

Queueing a script for the footer follows the same syntax as in script loader:

$scripts->add( 'handle', 'full/url/to/file.js', array( 'dependency' ), 'version' );
$scripts->add_data( 'handle', 'group', 1 );

Group 1 means queue for the footer, group 0 (zero) is the default.

#optimization

After more tests and research it seems the best two options for the WordPress adminadmin (and super admin) are either minifying all scripts and loading most in the footer or concatenating and compressing them on per page basis.

Minifying and loading scripts in the footer gives slightly slower performance with both cold and primed cache and would depend on the ability to set appropriate caching headers on the server. On the plus side this method would be compatible with the current plugins and wouldn’t introduce higher server load.

On the down side the loading speed improvement with primed cache would depend on the availability of mod_headers and/or mod_expires (presuming most installations are on ApacheApache Apache is the most widely used web server software. Developed and maintained by Apache Software Foundation. Apache is an Open Source software available for free.). It seems many hosts have either one or both modules installed but that still leaves a lot of installations without proper caching headers. In these cases the browser would keep checking for updated content which would increase the loading time with primed cache considerably.

Concatenating and compressing all scripts would give better speed improvement and we will be able to set all needed headers. The last couple of days I’ve been testing a method that uses a separate php file similar to how the Gears manifest is produced. This is the same basic method used by many “website php compressors”, a stand-alone php function that gets as argument the names of the needed scripts then concatenates and compresses them. It doesn’t use server side caching (that proved to be problematic on some servers) since the cold cache page hits on the admin are relatively few.

The advantage is that WordPress is not run second time on every cold cache page load so it uses a lot less server CPU time and memory. The disadvantage is that it would work only for the default scripts whose paths are included in the script loader. This also seems to be compatible with all existing plugins as any additional scripts are loaded after the single script and all requirements are satisfied.

Another disadvantage is that a few hosts seem to compress all php output in a non-standard way that may result in double compression. This method would also need “Optimization options” screen with a few checkboxes that would allow the user to enable/disable the concatenating and compression as it won’t be needed when using Gears.

#optimization