How to Optimize Your WordPress Site by Removing Unused JavaScript

Streamline your WordPress site's performance by eliminating unnecessary JavaScript files. This guide delves into effective methods to identify and remove these files, enhancing user experience and boosting search engine rankings.

Removing Unused JS on WordPress

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What is Unused JavaScript?

Before we dive into the optimization techniques, let's first understand what unused JavaScript actually means. Unused JavaScript refers to the JavaScript code that is not required for rendering the page or loading the main content. These files may be unnecessary because they are not part of the above-the-fold content, or because they are no longer used in the website's code.

Unused JavaScript can come from various sources, including third-party code like Google Analytics or Facebook tracking codes, plugins that load scripts based on specific pages or functionalities, and themes or page builders that heavily rely on JavaScript for their features.

The Impact of Unused JavaScript on Performance

Unused JavaScript files can have a significant impact on your site's performance and user experience. One key metric affected by unused JavaScript is the First Input Delay (FID), which measures a page's responsiveness based on user interaction. FID is a crucial component of the Core Web Vitals metrics, which are used by search engines to evaluate and rank websites.

When a page contains unused JavaScript, it can slow down the browser's rendering and loading process. This delay in page loading negatively affects user experience and can lead to higher bounce rates and lower search engine rankings.

How to Identify Unused JavaScript

To optimize your WordPress site by removing unused JavaScript, you need to identify the specific files that are causing performance issues. There are several tools you can use to analyze your site and pinpoint unused JavaScript files. Let's explore two popular options:

1. PageSpeed Insights

Google's PageSpeed Insights is a powerful tool that provides performance analysis and recommendations for your website. It also flags unused JavaScript files that need attention.

To use PageSpeed Insights, simply enter your site's URL, and it will generate a report with performance insights. Look for the "Remove unused JavaScript" recommendation under the Opportunities section. This will indicate if there are any unused JavaScript resources affecting your site's performance.

2. GTmetrix

GTmetrix is another valuable tool for analyzing your site's performance. It provides a detailed waterfall chart that shows all the resources loaded on your page, including JavaScript files.

After testing your site's performance on GTmetrix, navigate to the Waterfall Chart section. Click on the JS tab to view the list of JavaScript files. Look for large files or files from specific domains that may be contributing to unused JavaScript.

By using these tools, you can gain insights into the specific JavaScript files causing performance issues on your site.

Optimize Your WordPress Site by Removing Unused JavaScript

Now that we understand the impact of unused JavaScript and how to identify it, let's explore various methods to optimize your WordPress site by removing or reducing unused JavaScript.

1. Delay JavaScript Loading

Delaying JavaScript loading is a popular technique to optimize site performance by loading JavaScript files only when necessary. This technique is particularly effective for third-party code and heavy JavaScript files that are not required for the initial page render.

To delay JavaScript loading, you can use plugins like Wp Meteor or Wp Rocket. These plugins allow you to set a delay timer or load JavaScript files only after user interaction, such as scrolling or clicking a button. By delaying non-essential JavaScript, you can significantly improve your site's loading speed and enhance user experience.

2. Defer JavaScript Loading

In addition to delaying JavaScript, you can also defer the loading of non-critical JavaScript files. Defer means that the JavaScript files will be loaded after the main content of the page has finished rendering. This technique ensures that the critical elements of your page load first, improving the perceived speed for users.

Plugins like Wp Rocket offer the option to defer JavaScript files. By enabling this feature, the JavaScript files will be loaded asynchronously after the page has finished rendering. However, it's important to note that not all JavaScript files can be safely deferred, as some may be required for the proper functioning of your site. Carefully review and test the deferred JavaScript files to ensure there are no conflicts or errors.

3. Minify JavaScript

Minifying JavaScript is a technique that reduces the size of JavaScript files by removing unnecessary characters and spaces. This optimization process can significantly improve page load times by reducing file size.

To minify JavaScript on WordPress, you can use plugins like LiteSpeed Cache or Wp Rocket. These plugins automatically minify your JavaScript files, removing unnecessary characters and optimizing the code for faster loading.

However, it's important to note that minification can sometimes cause issues if certain JavaScript files rely on specific formatting. Test your site thoroughly after minifying JavaScript to ensure there are no functionality or compatibility issues.

4. Remove Unused JavaScript with Asset Cleanup

Asset Cleanup is a powerful plugin that allows you to selectively disable or unload unused JavaScript and CSS files. With Asset Cleanup, you can analyze the scripts and stylesheets loaded on each page of your site and disable them where they are not needed.

To remove unused JavaScript with Asset Cleanup, install and activate the plugin on your WordPress site. Navigate to the plugin settings and enable the "Manage CSS & JS" feature. This will allow you to control the loading of scripts and stylesheets on individual pages or posts.

By selectively unloading unused JavaScript files, you can reduce the overall file size and improve your site's performance. Be cautious when removing JavaScript files and ensure that they are truly unused to avoid any functionality issues.

5. Disable Unused Plugin Modules

Another effective way to remove unused JavaScript is to disable unused plugin modules. Many plugins load JavaScript files for specific functionalities or modules. If you are not using certain modules on your site, disabling them can help reduce the number of unnecessary JavaScript files loading.

Plugins like RankMath or Perfmatters offer the option to disable unused modules. Simply navigate to the plugin settings, locate the modules you don't need, and disable them. This will prevent the loading of unnecessary JavaScript files associated with those modules.

However, it's important to carefully review the functionality of your site after disabling plugin modules to ensure there are no adverse effects on your site's performance or user experience.


In conclusion, removing unused JavaScript is a crucial step in optimizing your WordPress site's speed and improving user experience. By identifying and removing unnecessary JavaScript files, you can significantly reduce page load times and enhance Core Web Vitals metrics.

In this guide, we explored different methods to identify and remove unused JavaScript, including delaying, deferring, minifying, and removing unused JavaScript files. Each method offers unique benefits and considerations, so it's important to choose the approach that best suits your site's specific needs.

By implementing these optimization techniques, you can ensure that your WordPress site loads quickly, providing a seamless user experience and boosting your search engine rankings. Take the necessary steps to remove unused JavaScript from your site and enjoy the benefits of a faster, more efficient website.