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Eliminate Render-Blocking Javascript: Javascript Explained

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In today’s digital world, web developers must ensure they are providing their users with the best possible experience. One important tool in the web developer’s toolkit is eliminating render-blocking Javascript. In this article, we’ll discuss what render-blocking Javascript is, the benefits of removing it, tips for optimizing your website, strategies for eliminating it, and other best practices.

What is Render-Blocking Javascript?

Render-blocking Javascript is a type of code that prevents a website from loading quickly. When a browser reads a web page, it reads the HTML first before it starts to download and run any other elements, like images and scripts. If a page has render-blocking Javascript, the browser will wait for the Javascript to finish downloading before the page can be displayed. This can cause the page to load slowly, which leads to a poor user experience.

To improve page loading speed, developers should use techniques such as asynchronous loading, which allows the browser to download and execute the Javascript while the page is still loading. This can help to reduce the amount of time it takes for a page to be displayed, resulting in a better user experience.

Benefits of Removing Render-Blocking Javascript

Removing render-blocking Javascript can have many benefits for your website. Faster page loading times lead to fewer abandonment issues, which can improve your website’s conversion rates. Having a speedy website can also help you rank higher in search engine results pages. Moreover, removing render-blocking Javascript can allow you to make better use of caching, and speed up subsequent page loads. Finally, reducing your reliance on render-blocking Javascript can help ensure your website remains compatible on a variety of devices.

In addition, removing render-blocking Javascript can help reduce the amount of data that needs to be transferred between the server and the browser, which can help reduce your website’s bandwidth usage. This can be especially beneficial for websites that receive a lot of traffic, as it can help reduce the strain on your server. Furthermore, removing render-blocking Javascript can help reduce the amount of code that needs to be parsed by the browser, which can help improve the overall performance of your website.

Tips for Optimizing Your Website

The key to optimizing your website is to ensure your pages are as light as possible. One way to do this is by compressing any images you use. You may also want to consider using a content delivery network to serve your files, allowing the browser to access them from multiple servers. Additionally, you can reduce the amount of Javascript present on your page by implementing lazy loading and deferring scripts. Finally, consider minifying any code you include, as this can help reduce download time.

You should also consider optimizing your website for mobile devices. This can be done by using a responsive design, which will automatically adjust the layout of your website to fit the device it is being viewed on. Additionally, you should ensure that any images you use are optimized for mobile devices, as this can help reduce loading times. Finally, you should consider using a caching system to store frequently accessed data, which can help reduce the amount of data that needs to be downloaded each time a user visits your website.

How to Avoid Render-Blocking Javascript

In order to avoid render-blocking Javascript, you should be mindful about the scripts you include on your page. When possible, try to use non-blocking scripts that don’t prevent the page from loading and display your content immediately. Additionally, try to reduce the number of scripts you include in order to make your pages as light as possible. Another way to avoid render-blocking Javascript is to use asynchronous scripts that load in the background while the rest of the page is being rendered.

You can also use the defer attribute to delay the loading of scripts until after the page has been rendered. This will ensure that the page is displayed quickly and that the scripts are loaded afterwards. Additionally, you can use the async attribute to load scripts asynchronously, which will allow the page to render while the scripts are being loaded.

Strategies for Eliminating Render-Blocking Javascript

There are a few different strategies you can use to eliminate render-blocking Javascript. One way is to inline your scripts by including them directly in your HTML document instead of relying on external files. This can help reduce the number of requests being made and improve the page’s loading time. You should also consider using a tool like Google’s PageSpeed Insights or PHP Accelerator to help identify any render-blocking scripts and manage them properly. Finally, you should look into using tools like Gulp or Grunt to automate the process of minifying and optimizing your code for faster page loads.

Another strategy for eliminating render-blocking Javascript is to use asynchronous loading. This means that the scripts will be loaded in the background while the page is loading, so that they don’t block the rendering of the page. This can help improve the user experience, as the page will appear to load faster. Additionally, you can use a content delivery network (CDN) to serve your scripts, which can help reduce the number of requests being made and improve the page’s loading time.

Tools to Help You Identify and Remove Render-Blocking Javascript

There are several tools available that can help you identify any render-blocking Javascript on your website. Google’s PageSpeed Insights and PHP Accelerator are two popular tools that can detect any scripts that are slowing down the loading process and provide advice on how best to remedy the issue. Additionally, libraries like Ember.js, React.js, and Vue.js offer render-deferring techniques that can help you identify and remove any superfluous scripts.

In addition to the tools mentioned above, there are also a number of browser extensions that can help you identify and remove render-blocking Javascript. These extensions can be used to quickly identify any scripts that are slowing down the loading process and provide advice on how to optimize them. Additionally, some of these extensions can also be used to minify and compress Javascript files, which can further reduce the amount of time it takes for a page to load.

Best Practices for Working with JavaScript

When working with JavaScript, it’s important to keep in mind some best practices. Be sure you’re using declarative scripting instead of imperative scripting whenever possible. This can help ensure that your code is fast and efficient. Additionally, be mindful of the size of libraries or frameworks you use and try to use pre-built apps or components instead. Always make sure to go through the process of debugging your code before pushing it live, and use a tool like JSLint or ESLint to identify any potential issues with your code.

How to Test Your Website Performance After Removing Render-Blocking Javascript

Once you’ve eliminated any render-blocking Javascript, you should conduct tests to ensure it had the desired effect on your site’s performance. One way to do this is through the use of tools such as WebPageTest or GTmetrix. These services allow you to measure the loading time of your pages before and after making optimizations. You can also use Google Analytics to track page load times or access data from Google Search Console about performance issues with your website.

Conclusion

In conclusion, eliminating render-blocking Javascript is essential for achieving fast page loading times and providing users with the best possible experience. By optimizing the scripts you include on your page and using tools such as Google’s PageSpeed Insights or PHP Accelerator to detect render-blocking scripts, you can help ensure your website loads quickly and efficiently. Additionally, being mindful of best practices when working with JavaScript can help make sure roll-out processes are quick and easy.

Picture of Sarang Sharma

Sarang Sharma

Sarang Sharma is Software Engineer at Bito with a robust background in distributed systems, chatbots, large language models (LLMs), and SaaS technologies. With over six years of experience, Sarang has demonstrated expertise as a lead software engineer and backend engineer, primarily focusing on software infrastructure and design. Before joining Bito, he significantly contributed to Engati, where he played a pivotal role in enhancing and developing advanced software solutions. His career began with foundational experiences as an intern, including a notable project at the Indian Institute of Technology, Delhi, to develop an assistive website for the visually challenged.

Written by developers for developers

This article was handcrafted with by the Bito team.

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