How to Fix Render-Blocking JavaScript and CSS in WordPress
Do you want to eliminate render-blocking JavaScript and CSS in WordPress? If you test your website on Google PageSpeed insights, then you will likely see a suggestion to eliminate render-blocking scrips and CSS. In this article, we will show you how to easily fix render blocking JavaScript and CSS in WordPress to improve your Google PageSpeed score.
What is Render-Blocking JavaScript and CSS?
Every WordPress site has a theme and plugins that add JavaScript and CSS files to the front-end of your website. These scripts can increase your site’s page load time, and they can also block rendering of the page.
A user’s browser will have to load those scripts and CSS before loading rest of the HTML on the page. This means that users on a slower connection will have to wait a few milliseconds more to see the page.
These scripts and stylesheets are referred to as render-blocking JavaScript and CSS.
Website owners who are trying to achieve the Google PageSpeed score of 100 will need to fix this issue to attain that perfect score.
1. Fix Render Blocking Scripts and CSS with Autoptimize
This method is simpler and recommended for most users.
First thing you need to do is install and activate the Autoptimize plugin. For more details, see our step by step guide on how to install a WordPress plugin.
Upon activation, you need to visit the Settings » Autoptimize page to configure the plugin settings.
You can start by checking the box next to JavaScript Options and CSS Options and then click on the save changes button.
You can now test your website using PageSpeed tool. If there are still render blocking scripts, then you need to come back to the plugin’s settings page and click on ‘Show Advanced Settings’ button at the top.
Here you can allow plugin to include inline JS and remove scripts that are excluded by default like seal.js or jquery.js.
Next, scroll down to CSS option and allow plugin to aggregate inline CSS.
Click on the ‘Save changes and Empty Cache’ button to save your changes and empty plugin cache.
Once you are done, go ahead and check your website again with the PageSpeed tool.
Make sure that you thoroughly test your website to see that nothing is broken by optimizing your JavaScripts or CSS.
2. Fix Render Blocking JavaScript using W3 Total Cache
This method requires a little more work and is recommended for users already using W3 Total Cache plugin on their website.
First you will need to install and activate the W3 Total Cache plugin. If you need help, then see our guide on how to install and setup W3 Total Cache for Beginners.
Next, you need to visit Performance » General Settings page and scroll down to Minify section
First you need to check ‘Enable’ next to Minify option and then select ‘Manual’ for minify mode option.
Click on the save all settings button to store your settings.
Next, you need to add the scripts and CSS that you want to minify.
You can get the URLs of all the scripts and stylesheets that are render blocking from Google PageSpeed Insights tool.
Under the suggestions where it says: ‘Eliminate render-blocking JavaScript and CSS in above-the-fold content’, click on ‘Show how to fix’. It will show you the list of scripts and stylesheets.
Take your mouse over to a script and it will show you the full URL. You can select this URL and then use your keyboard’s CTRL+C (Command+C on Mac) keys to copy the URL.
Now head over to your WordPress admin area and go to Performance » Minify page.
First you need to add JavaScript files that you want to be minified. Scroll down to JS section and then under the ‘Operations in areas’ set the embed type to ‘Non-blocking async’ for the <head> section.
Next, you need to click on the ‘Add script’ button and then start adding script URLs that you copied from Google PageSpeed tool.
Once you are done, scroll down to CSS section and then click on the ‘Add a stylesheet’ button. Now start adding stylesheet URLs you copied from Google PageSpeed tool.
Now click on the ‘Save settings and purge cache’ button to store your settings.
Visit the Google PageSpeed tool and test your website again.
Make sure that you also test your website thoroughly to see that everything is working fine.
