Simple Custom CSS and JS Review - In-Depth Analysis
Easily add Custom CSS or JS to your website with an awesome editor.
Performance Overview
User Rating
4.4/5 (based on 103+
reviews)
Active Installations
600,000+
Update Frequency
Average
It is calculated using the weighted average of same category
plugins.
Security Score
5 / 10
(Medium Risk)
It is calculated using the weighted average of all versions.
What It Does
Customize your WordPress site's appearance by easily adding custom CSS and JS code without even having to modify your theme or plugin files. This is perfect for adding custom CSS tweaks to your site.
The plugin features a text editor with syntax highlighting, allowing you to print the code inline or include it in an external file. You can choose to print the code in the header or the footer, add CSS or JS to the frontend or the admin side, and add as many codes as you want. Your changes will be preserved even when you change the theme.
Comparing to Alternatives
Simple Custom CSS and JS competes in a crowded field of code-snippet plugins, ranging from minimal CSS-only editors to more specialized tools targeting page builders like Elementor. Its broader feature set for handling CSS, JS, and HTML across different locations sets it apart from simpler alternatives.
Strengths
- Supports CSS, JS, and HTML in one plugin rather than just CSS alone
- Flexible loading options: inline or external, header, body, or footer, front end or admin
- Syntax highlighting and per-snippet enable/disable controls
- Versioned file storage that eases local development workflows
- Responsive developer support according to multiple reviewers
Weaknesses
- More complex interface than bare-bones CSS-only alternatives
- One documented XSS vulnerability in older versions shows a need for prompt updates
- Some editing conveniences like bracket matching and undo are still lacking
User Sentiment Analysis
With a 4.4/5 average from 103 ratings, sentiment is largely positive, with nearly 80% of users giving five stars. However, an 12.6% share of 1-2 star reviews signals that a small but notable minority ran into serious issues.
Positive highlights
- tomcudworth84 praised the plugin's reliability and the developer's transparency after a security code review
- Bjarne Oldrup called it 'rock solid' after years of use, highlighting its rich feature set for a free plugin
- Zayadur highlighted conditional location rules, versioned file storage, and standout support
- michaelmatzkin appreciated quick support in resolving a plugin compatibility issue
- joseeneveu said it solved editing problems that other CSS plugins couldn't after weeks of trying
Common complaints
- Plugin flushes permalink settings on install without admin confirmation, disrupting other plugins' configurations
Weaknesses
- A medium-severity authenticated XSS vulnerability was identified in versions up to 3.3, though fixed in 3.4
- Minor editing UX gaps such as inconsistent bracket-matching feedback and no undo function
- Automatic permalink flushing on install caused real disruption for at least one site owner
Who Should Use This?
Best for
Developers and site owners who need a flexible, no-cost way to add custom CSS, JS, or HTML snippets across specific pages, posts, or site-wide locations. It suits users comfortable with a slightly more feature-rich interface in exchange for greater control over where and how code loads.
Not ideal for
Users who want the simplest possible CSS-only editor, or who are wary of a plugin that has had at least one known XSS vulnerability in its history should ensure they're running the latest version. Site owners cautious about install-time changes to permalinks should also test carefully in staging first.
Pricing & Value
Free version includes
The free version is fully featured, offering CSS, JS, and HTML snippet management with syntax highlighting, flexible load locations (header, body, footer), inline or external loading, and simple per-snippet toggling — a generous feature set with no paywall.
Final Verdict
Simple Custom CSS and JS earns its strong reputation through a genuinely useful, feature-rich free offering that covers CSS, JS, and HTML snippet management with unusual flexibility for a no-cost tool. The overwhelmingly positive reviews reflect real satisfaction with both functionality and developer support, though the permalink-flushing complaint and a past authenticated XSS vulnerability are worth noting for cautious users.
For anyone needing more than a bare CSS editor and wanting granular control over snippet placement without paying for a premium plugin, this remains a solid choice — provided it's kept updated and tested before deployment on production sites. Those seeking the absolute simplest tool, or who are especially security-conscious, may want to weigh the lighter alternatives listed above.
Other Notable Features
Here are a few other notable features of this free
Simple Custom CSS and JS plugin.
FAQ
If you write multiple codes of the same type (for example: two external CSS codes), then all of them will be printed one after another
When you click the Save button the codes will be cached in files, so there are no tedious database queries.
No, the code is printed exactly as in the editor. It is not modified/checked/validated in any way. You take the full responsability for what is written in there.
Try one of the following:
1. If you are using any caching plugin (like “W3 Total Cache” or “WP Fastest Cache”), then don’t forget to delete the cache before seing the code printed on the website.
2. Make sure the code is in Published state (not Draft or in Trash).
3. Check if the wp-content/uploads/custom-css-js folder exists and is writable
The CSS and JS are independent of the theme and they will persist through a theme change. This is particularly useful if you apply CSS and JS for modifying a plugin’s output.
For the moment only plain CSS is supported, but you can check out the Pro version in case you need a CSS preprocessor.
Yes. You can upload an image to your Media Library, then refer to it by its direct URL from within the CSS stylesheet. For example:
div#content {
background-image: url(‘http://example.com/wp-content/uploads/2015/12/image.jpg’);
}
By default only the Administrator will be able to publish/edit/delete Custom Codes. On the plugin activation there is a role created called Web Designer. You can assign this role to a non-admin user in order to allow to publish/edit/delete Custom Codes. On the plugin’s Settings page there is an option to remove this role.
The URL for the linked Codes is built just like the URL for other media (from Media Library) by using the WordPress Address option found on the WP Admin -> Settings -> General page, as shown in this screenshot. If the WordPress Address has HTTPS in the url, then the Custom Codes and all the other media will have HTTPS in the url.
Contributors and developers
“Simple Custom CSS and JS”
is open source software. The following people have
contributed to this plugin.
