Render-blocking CSS is not the only factor that affects your site speed. However, it can make a major difference in load times. The fewer and lighter the scripts on your site are the better its speed.
Your website runs better whenever its code is clean and minimal. Since there is always a bit of leftover code, browsers by default will try to load everything at once. This includes the render-blocking scripts. Your job is to ensure your website loads the scripts that are necessary, correct and usable when visitors first land on a page. After that, the rest of the scripts that are not really observable by visitors can load.
To remove render-blocking scripts, you first have to identify the scripts, which are actually causing problems. As already mentioned above, Google’s PageSpeed Insights is the recommended tool to help you in diagnosing the scripts slowing down your WordPress website. All you have to do is enter your URL into Google PageSpeed Insights and it will show you your speed score along with a list of the scripts that are responsible for slowing down your page.
Defer Loading of Java Script:
- Autoptimize Plugin: This plugin was designed to deal specifically with issues brought up by recommendation systems such as PageSpeed Insights. Simply install and activate the Autoptimize plugin. Once activated, go to Settings » Autoptimize page to configure the plugin settings.
All websites are unique in their own way. That is why it is important for you to experiment with the different options to see what works best for you. Please note that if you happen to minified or moved scripts incorrectly, you can completely break your site. Therefore, it is critical that you test your settings before letting them run.