Adding Javascript to the Administrator Template

Question

Is there a way to add Javascript to the Joomla Administrator template without creating a child template?

Something equivalent to /media/templates/administrator/atum/css/user.css for Javascript.

Answer 1

You could create a system plugin that only works in the back-end and loads some JavaScript file.

Probably with something like:

defined('_JEXEC') or die;

use Joomla\CMS\Application\CMSApplication;
use Joomla\CMS\HTML\HTMLHelper;
use Joomla\CMS\Plugin\CMSPlugin;

class PlgSystemPluginname extends CMSPlugin
{

  protected $app;

  public function onAfterRender()
  {
    // Quit this when the app is not in the administrator back-end
    if (!$this->app->isClient('administrator'))
    {
      return;
    }

    // Load some JavaScript file
    HTMLHelper::_('script','com_foo/foo.js', 
    ['version' => 'auto', 'relative' => true]);
  }
}

Answer 2

-Using the web asset manager from Joomla 4 could help : https://docs.joomla.org/J4.x:Web_Assets

-For a quick solution or test purposes, you may add your javascript in the /media/templates/administrator/atum/js/template.min.js but watch out for updates which might remove the content(you could do a template override then)