I'm trying to get started with Joomla extension development, and am having trouble following along with simple examples.

Where is the Jhtml class defined and/or documented? I see it being used in examples and extensions that come with Joomla, but I can't find any current documentation on it. Existing links into https://api.joomla.org/cms-3/ all appear to be broken, and my attempts to grep the Joomla source have not turned up anything.


Please tell me whether I understand this correctly. It looks like libraries/classmap.php calls JLoader::registerAlias to dynamically alias the name JHtml to HTMLHelper. I'm unable to find documentation on JHtml because there is no such class.

  • Your update is entirely correct (surprised no one answered this before now). Anytime you're looking for a a class definition, especially for one that starts with "J", start in classmap.php; you'll probably get there faster.
    – Arlen
    May 14, 2020 at 14:21

3 Answers 3


The JHtml class was changed to \Joomla\CMS\HTML\HTMLHelper (/libraries/src/HTML/HTMLHelper.php) since 3.8 as a part of namespacing the core.

I believe you can still use documentation (and API ref) of the old JHTML class.

The best way to learn everything about it - use IDE like PHPStorm for example, and you'll get a lot of useful hints, not to mention class propositions based on partial name typed.

Also what you may put a file like this one: _ide_helper.php in the root of your project to make your transition from <3.8 smoother with IDE.

  • Hey alexandr could add a link to the old documentation to yr post? Dec 19, 2017 at 9:17
  • Added, but it's almost safe to say that Joomla has almost no documentation for developers, but PHPDocs of the methods are useful.
    – Alexandr
    Dec 19, 2017 at 12:29

As of Joomla 3.8, the majority of classes have been namespaced but with a fallback for when migrating to J4.

So, you can still use JHtml::XXX, but the new approach is:

use Joomla\CMS\HTML\HTMLHelper;

HTMLHelper::_('script', 'path/to/file.js');
HTMLHelper::_('stylesheet', 'path/to/file.css');

You can find the source code for the HTMLHelper class here:


The code is still the same as it was before, so you can continue reading through the current Joomla documentation for JHtml.

  • But what does this do specifically? Does it add the script to the head of the page? YES IT DOES!
    – Eoin
    Jun 10, 2019 at 19:52
  • So we should not use JFactory::getDocument(); anymore?
    – Eoin
    Jun 10, 2019 at 19:54
  • 1
    @Eoin, you can still use it if you want, but I'd suggest against it. HTMLHelper has additional features such as override support.
    – Lodder
    Jun 11, 2019 at 7:30
  • 1
    Let say you create an extension and load a Javascript file within it using HTMLHelper, users will be able to copy/paste the file into their template directory and make modifications to it if they want. Joomla will automatically load the overridden JS file from the template directory if it exists.
    – Lodder
    Jun 11, 2019 at 11:28
  • 1

Yeah the google links are messed up because of the namespacing and shifting changes. Most of the Joomla core classes are all now in libraries/src here:


JHtml is in the HTML folder. The api listing is here:


As for "Documentation"... lol.

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