The Additional CSS and Additional JavaScript fields in Moodle are commonly used for small interface adjustments. They offer an easy way to apply branding updates or front end tweaks without modifying theme files. However, when several administrators edit these fields at the same time, Moodle often removes or replaces existing code. This creates unpredictable styling, broken scripts, and recurring support issues that are difficult to trace. This article explains why this behavior occurs and outlines stable solutions for long term collaboration, quality control, and maintainable development.
To say that Mindfield Consulting is Planet SHIFT Inc.’s key strategic technology partner is an understatement. They play a pivotal role in helping us delight our clients, providing valuable guidance, forefront thinking, and creative, sustainable solutions — simply – honest and excellent work. As a change agent, I rely on my Mindfield partnership to unlock the possible, and for just under a decade I have never been disappointed. Our clients’ projects range in complexity and criticality, and the credibility of my company’s brand accelerates when Mindfield is included in the assignment. We reinvent businesses together.
Eileen Kirk
review Source: Google Reviews
Outline
-
-
What the Additional CSS and JavaScript Fields Are Designed For
-
Why Overwriting Happens When Multiple Administrators Work at the Same Time
-
Impact on Administrators and Site Operations
-
Workarounds and Long Term Solutions
-
Comparison Table
-
Saving Your Style Sheet: Why a Moodle Expert Makes All the Difference
-
Frequently Asked Questions(FAQs)
-
What the Additional CSS and JavaScript Fields Are Designed For
The fields exist for quick changes that do not require theme development. Administrators typically use them for:
-
Styling adjustments that are too small for a full theme update
-
Fixing layout issues or hiding unwanted blocks
-
Adding branding elements
-
Adding simple front end interactions
-
Tweaking specific course or dashboard elements
These fields give administrators immediate control without needing access to theme code.
However, they are not designed to support large scale customization or multi person collaboration.
Why Overwriting Happens When Multiple Administrators Work at the Same Time
Moodle stores the entire content of each field as one configuration value.
When several administrators open the same page, the system does not track versions or detect concurrent editing.
The usual failure scenario looks like this:
-
Admin A adds new styling but does not save yet
-
Admin B opens the same field without seeing Admin A’s edits
-
Admin B saves their version
-
Moodle replaces the older value with B’s version
-
Admin A saves afterward
-
The system replaces everything again, removing all of B’s content
There are several technical reasons for this behavior:
-
Moodle does not lock the field when someone is editing
-
Moodle does not track versions or record changes
-
Theme caches are rebuilt after each save which overwrites any previous CSS
-
The field is a single stored text value with no merge capability
This is expected behavior based on Moodle architecture, not a system error.
Impact on Administrators and Site Operations
When the Additional CSS or JavaScript fields are overwritten, several issues appear:
- Loss of custom work: Design elements disappear, branding is lost, or layout breaks without warning.
- Unpredictable presentation: Code that worked yesterday stops working after another administrator saves unrelated edits.
- Support complexity: The cause is difficult to trace because the change logs do not show the overwritten content.
- High risk during urgent updates: Simple adjustments can ripple through the entire interface, affecting students, teachers, and public facing pages.
Because of these risks, large organizations and multi admin environments should avoid using these fields as a long term solution.
Workarounds and Long Term Solutions
Below are the recommended approaches ranked from most stable to least stable.
1. Create a Local Plugin for CSS and JavaScript (Best Long Term Solution)
A small local plugin can contain dedicated CSS and JavaScript files.
Advantages include:
-
No accidental overwriting
-
Full control in code repositories
-
Clear version history
-
Works even if the team switches themes
-
Proper deployment through Git
This method is the most stable and collaboration friendly.
2. Use Git Based Collaboration With Custom Theme Files
Store your CSS and JavaScript inside theme files such as:
-
theme/style/custom.css -
theme/javascript/custom.js
Then manage them in Git for:
-
Multi person editing
-
Proper version tracking
-
Code review
-
Conflict resolution
-
Safe deployment process
This is the standard approach for development teams.
3. Use Theme SCSS Options Instead of the Additional CSS Field
Most modern Moodle themes support SCSS imports.
This allows the team to place styling inside structured files that can be stored in Git.
This approach is cleaner and reduces the risk of accidental loss because the field is not used for large blocks of code.
4. Create Internal Administrator Rules
If development resources are limited, teams can adopt simple administrative rules:
-
Only one CSS or JavaScript owner
-
Mandatory backups before editing
-
Shared document that records modifications
-
Editing only during scheduled windows
This reduces conflict risk but does not fully protect against loss.
Comparison Table
| Method | Advantages | Limitations |
|---|---|---|
| Additional CSS or JavaScript Field | Fast and accessible | Very high risk of overwriting |
| Local Plugin | Safe, clean, supports collaboration | Requires development work |
| Git Based Theme Files | Full control and history | Requires technical workflow |
| SCSS in Themes | More stable than text fields | Needs theme access |
| Administrator Workflow Rules | Easy to set up | Human error can still remove content |
Saving Your Style Sheet: Why a Moodle Expert Makes All the Difference
A Moodle expert brings a level of architectural understanding that prevents the issues commonly caused by the Additional CSS and JavaScript fields. They know how Moodle compiles SCSS, how theme caches behave, and how different interface layers interact. Instead of relying on a single text field that can be overwritten by the next administrator, an expert builds a stable foundation using local plugins, structured SCSS files, and version controlled workflows. This ensures that every change has a clear history, predictable behavior, and reliable deployment.
Beyond writing code, a Moodle expert helps organizations avoid hidden risks. They create documentation, introduce clean development practices, and design processes that allow multiple administrators to work together without breaking the site. When unexpected issues appear, an expert can resolve them quickly because they understand the deeper architecture and know how to isolate styling conflicts or JavaScript failures. The result is a Moodle environment that is easier to maintain, safer for collaboration, and far more resilient to accidental edits or rushed updates.
