What is MooTools used for in Joomla?

On Joomla 3 it opens SqueezeBox modals and builds captions for images that use the caption class. Older templates also use it for sliders and accordions. Joomla 4 and newer core do not use it.

Does the latest Joomla still use MooTools?

No. Joomla 4 removed it, and Joomla 5 and 6 did not bring it back. A request for mootools-core.js on those versions comes from a template or extension.

Why do people remove MooTools?

The usual reasons are unused JavaScript on article pages, conflicts with jQuery over $ , and the fact that the library has had no real release since 2016. PageSpeed scores are a side effect, not the only reason.

Why are mootools-core.js and caption.js on every article?

Joomla 3 content layouts call JHtml::_('behavior.caption') . That behavior loads both files so old img.caption markup still gets a caption.

Will my site break if I remove it?

It breaks wherever a template or extension still calls SqueezeBox, caption.js , or MooTools effects. Test those pages. The administrator on Joomla 3 should keep the library.

Should I delete mootools-core.js over FTP?

No. On Joomla 3 that only creates a 404, because core still prints the URL. Stop the behavior or unset that URL. On Joomla 4+ the file is not part of core.

Is MooTools the same as jQuery?

No. Joomla 3 loaded both. jQuery remains an optional Web Asset Manager asset on current Joomla. MooTools does not.

What replaces caption.js and SqueezeBox?

Use figure and figcaption for captions. Use a Bootstrap modal, or the Joomla 4 dialog, instead of class="modal" .

Can someone remove it without breaking the template?

Yes. That means finding the caller, replacing captions and lightboxes, then unsetting only those scripts. Request a Joomla upgrade audit if the template still depends on it.

Joomla

How to Remove MooTools from Joomla

MooTools is gone from Joomla 4, 5, and 6. On Joomla 3 it still powers SqueezeBox and caption.js. Here is how to remove only those scripts without stripping jQuery.

Abhilash Sahoo

Sep 18, 202613 min read

Frequently asked questions

Share this article

Joomla

Written by

Abhilash Sahoo

Abhilash Sahoo, with over 16 years of experience, is Founder & CEO of Infyways Solutions. He builds web platforms and eCommerce on Joomla, WordPress, Shopify, Magento, and OpenCart, plus modern stacks like Next.js, React, Node.js, and Python, with AI agents, automation, and headless CMS when products need to scale.

Keep reading

View all

Tell us what you're building. Whether it's a new site, an online store, a mobile app, or something that needs AI under the hood, we'll get back to you within a business day.

Free consultation

No commitment, no pressure

Reply within 24 hours

Usually much faster

How to Remove MooTools from Joomla

Frequently asked questions

Abhilash Sahoo

Related articles

Joomla Turns 21 Today: Why Its Best Days Are Still Ahead

Procedure to Upload an Excel Sheet on Joomla Website

Joomla 3 to Joomla 6 Upgrade: The Path You Cannot Skip

Have a project in mind? Let's talk about it.

Tell us about your project

Services

AI & Automation

Industries

Company

Technologies