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Async JS and CSS

By dmikam

Performance & Optimization / Caching Solutions

Reviewed by Omar Dabbas

Trusted WordPress expert with 20+ years of experience evaluating plugins for the WP ecosystem.

Async JS and CSS Review - In-Depth Analysis

Improves web page performance by converting render-blocking CSS and JS files into non-render-blocking ones.

Performance Overview

WPS Score

6.8/10

User Rating

4.2/5 (based on 51+ reviews)

Active Installations

700+

Update Frequency

Below Average It is calculated using the weighted average of same category plugins.

Security Score

1 / 10 (Very Low Risk) It is calculated using the weighted average of all versions.

What It Does

This plugin enhances your website's loading speed by changing how CSS and JavaScript files are loaded. Instead of blocking the rendering of the page, it allows these files to load asynchronously, which means users see content faster.

By utilizing this plugin, webmasters can improve their site's performance metrics, which is crucial for search engine optimization. Google PageSpeed Insights highlights the importance of reducing render-blocking resources, and this plugin addresses that issue effectively.

All scripts from other plugins are loaded asynchronously, and CSS files can be moved to the end of the document or inserted inline for better performance. The plugin offers various configuration methods to optimize loading times.

Comparing to Alternatives

Async JS and CSS is a plugin designed to optimize JavaScript and CSS loading asynchronously, improving page speed. It faces competition from several well-established plugins offering similar optimization features.

Top alternatives

Strengths

Effectively improves page speed by asynchronously loading JS and CSS
Simple to use with minimal configuration needed
No known security vulnerabilities reported
Free to use without a paid version
Receives mostly positive user ratings with a 4.2 average

Weaknesses

Can cause compatibility issues with some themes and plugins like WPtouch and Revslider
May break site functionality on complex sites or with certain page builders like Divi
Lack of recent support responses can leave issues unresolved
Some users report that page load times can increase despite optimization

User Sentiment Analysis

With a 4.2 average rating from 51 reviews, most users appreciate the plugin's performance benefits, though a notable minority report serious issues. Positive feedback highlights its effectiveness, while negative reviews focus on compatibility and stability problems.

Positive highlights

"Does the job and helps to do more tweaks." — Abhishek Ghosh
"Nice job" — lanuevareligiondt
"Good plugin" — lanuevareligiondt

Common complaints

Prevents proper loading of theme JavaScript and CSS, causing plugin conflicts
Breaks site functionality, notably disabling sliders like Revslider
Crashes multiple page functions and can require site restoration from backups

Weaknesses

Compatibility issues with popular themes and plugins
Potential to cause site crashes and broken features
Limited recent support and updates

Who Should Use This?

Best for

Users with simple sites looking for a free and straightforward way to asynchronously load JavaScript and CSS to improve page speed.

Not ideal for

Users with complex sites, those relying on specific plugins like WPtouch, Revslider, or Divi, or those who require robust support and guaranteed compatibility.

Pricing & Value

Free version includes

The free version includes asynchronous loading of JavaScript and CSS to improve site speed without any cost.

Final Verdict

Async JS and CSS offers a valuable free solution for improving website speed by asynchronously loading scripts and styles. It is well-rated by most users and has no known security vulnerabilities, making it a safe choice for simple sites.

However, it has significant compatibility issues that can break site functionality, especially on complex setups or with certain popular plugins. Users should proceed with caution and ensure they have backups before use. Alternatives may offer more robust support and compatibility.

Other Notable Features

Here are a few other notable features of this free Async JS and CSS plugin.

Async

Asynchronous

JavaScript optimization

CSS optimization

Performance improvement

Screenshots

FAQ

Like any other plugin

1. Upload `asyncJSandCSS` folder to the `/wp-content/plugins/` directory  2. Activate the plugin through the 'Plugins' menu in WordPress  3. Configure the plugin if needed (Settings/Async Settings)

Plugin can affect only those files loaded using worpdress’s queue (using wp_enqueue_script and wp_enqueue_style), so if you include your CSS file inserting into head.php of your theme – it WILL NOT be affected and will be loaded in standart render-blocking way.

You just need to include cache configuration in your .htaccess file. For example:

<IfModule mod_expires.c>     ExpiresActive On     ExpiresByType image/gif "access plus 6 month"     ExpiresByType image/jpeg "access plus 6 month"     ExpiresByType image/png "access plus 6 month"     ExpiresByType application/javascript "modification plus 1 month"     ExpiresByType text/css "modification plus 1 month" </IfModule>

Add this line to exceptions box:

jquery

or if you are using jQuery from Google Hosted Libraries, you need to put:

jquery.min.js

Add this line to exceptions box:

colorbox colorbox-wrapper

You just need to include cache configuration in your .htaccess file. For example:

<IfModule mod_expires.c>     ExpiresActive On     ExpiresByType image/gif "access plus 6 month"     ExpiresByType image/jpeg "access plus 6 month"     ExpiresByType image/png "access plus 6 month"     ExpiresByType application/javascript "modification plus 1 month"     ExpiresByType text/css "modification plus 1 month" </IfModule>