Eliminate Render-Blocking Resources: An effective way to improve your websites speed

If you own a website, you probably already know that website performance is crucial for user experience and search engine optimization. Slow-loading pages can drive users away and hurt your search engine rankings. One of the most significant issues that can affect website performance is Eliminate Render-Blocking Resources resources. In this blog post, we will discuss render-blocking resources, how they affect your website, and how you can eliminate them to improve your website’s performance.

Eliminate Render-Blocking Resources

What are Render Blocking Resources?

When a browser loads a web page, it goes through a process called rendering, which includes downloading and parsing various resources such as HTML, CSS, JavaScript, and images. Eliminate Render-Blocking Resources are those that prevent the browser from rendering the page until they are fully downloaded and parsed.

For example, let’s say your website’s CSS file is a render-blocking resource. This means that the browser won’t start rendering the page until the CSS file is fully downloaded and parsed. If the CSS file is large or takes a long time to download, it can significantly slow down your website’s loading time and hurt user experience.

Why are Eliminate Render-Blocking Resources a Problem?

As mentioned earlier, Eliminate Render-Blocking Resources can significantly slow down your website’s loading time. When a user visits your website, they expect it to load quickly, and if it takes too long to load, they may leave and never come back. This can hurt your website’s bounce rate and lead to lost revenue.

Moreover, Eliminate Render-Blocking Resources can also affect your website’s search engine rankings. Google’s algorithm takes into account various factors, including website performance, when ranking websites. If your website is slow and takes too long to load, it can hurt your search engine rankings and make it harder for users to find your website.

Eliminate Render-Blocking Resources
Eliminate Render-Blocking Resources

How to Identify Render Blocking Resources?

To identify render-blocking resources on your website, you can use tools like Google PageSpeed Insights, which is a free tool that analyzes your website’s performance and provides suggestions to improve it.

When you run your website through PageSpeed Insights, it will give you a score from 0-100 based on various factors, including page speed and user experience. It will also provide suggestions to improve your website’s performance, including eliminating render-blocking resources.

PageSpeed Insights will also show you a list of Eliminate Render-Blocking Resources on your website, including CSS and JavaScript files. It will also show you the size and loading time of each resource, making it easy to identify which resources are causing the most significant delays.

Types of Eliminate Render-Blocking Resources

To eliminate render-blocking resources, we need to understand the types of resources that can cause delays in rendering a web page. The following are the most common types of render-blocking resources:

CSS Files

  1. CSS files define the style and layout of a web page. They are essential for creating visually appealing websites. However, CSS files can also be render-blocking resources if they are not loaded efficiently. If a web page has a large CSS file, it can prevent above-the-fold content from rendering quickly, leading to a slower page load time.

JavaScript Files

  1. JavaScript files add interactivity and dynamic content to web pages. However, like CSS files, they can also be render-blocking resources. If a web page has a large JavaScript file, it can prevent the browser from rendering above-the-fold content until the file has finished loading.

Fonts

  1. Fonts are another type of resource that can cause delays in rendering a web page. Custom fonts, such as Google Fonts, can be render-blocking resources if they are not loaded efficiently. The browser needs to download the font files before it can render the text on the page. This can lead to slower page load times, especially if the font files are large.

Understanding Eliminate Render-Blocking Resources

Render-blocking resources are assets that must be loaded before a web page can be displayed. These resources include CSS files, JavaScript files, and web fonts, among others. When a browser encounters a render-blocking resource, it must pause rendering until the resource has been downloaded and parsed. This delay can negatively impact page speed and website performance.

Render-blocking resources can be categorized as critical and non-critical. Critical resources are essential for the initial rendering of the web page, while non-critical resources can be loaded later.

Identifying Render Blocking Resources

One of the most important parts to eliminate render-blocking resources is to identify them on your website, you can use tools like Google Pagespeed Insights, which will provide you with a list of resources that are blocking the rendering of your page.

Chrome DevTools is another great tool that allows you to identify and Eliminate Render-Blocking Resources. Simply open DevTools, navigate to the Network tab and reload your page. The resources that are marked as “blocking” are the Eliminate Render-Blocking Resources.

Eliminate Render-Blocking Resources is an essential step in improving website speed and user experience. The following are some of the ways to eliminate render-blocking resources:

Eliminate Render-Blocking Resources

How to Eliminate Render Blocking Resources

There are several ways to Eliminate Render-Blocking Resources and improve page speed and website performance.

1. Optimize Critical Resources:

Optimizing critical resources is the first step to Eliminate Render-Blocking Resources. Critical resources include CSS files, JavaScript files, and web fonts that are required for the initial rendering of the web page.

One way to optimize critical resources is to inline them in the HTML. Inlining involves placing the CSS and JavaScript code directly into the HTML file, which reduces the number of requests and eliminates the need for the browser to download external files.

Another way to optimize critical resources is to use a technique called critical CSS. Critical CSS involves extracting the CSS that is required for the initial rendering of the web page and embedding it directly into the HTML file. This reduces the number of requests and eliminates the need for the browser to download external CSS files.

Optimize Critical Resources

2. Defer Non-Critical Resources:

Defer non-critical resources to improve page speed and website performance is another important step to Eliminate Render-Blocking Resources. Non-critical resources include JavaScript files, images, and other assets that are not required for the initial rendering of the web page.

To defer non-critical resources, you can use the “defer” attribute in the HTML script tag, which tells the browser to defer the execution of the JavaScript code until after the page has been rendered.

Check out: Resource Loading

3. Optimize CSS Delivery:

Optimizing CSS delivery is another way to Eliminate Render-Blocking Resources. One way to optimize CSS delivery is to minify CSS files, which reduces the file size and improves load times.

You can also use a technique called lazy loading to defer the loading of CSS files until after the initial rendering of the web page.

4. Use Cache Plugins:

Cache plugins like W3 Total Cache and Litespeed Cache can improve website performance by caching resources and reducing the number of requests made to the server.

Caching also allows the browser to load previously downloaded resources from the cache, which reduces load times.

5. Remove Unused CSS and JavaScript:

Removing unused CSS and JavaScript files is another way to Eliminate Render-Blocking Resources. Unused CSS and JavaScript files can bloat the file size and slow down page load times.

You can use tools like PurifyCSS to remove unused CSS files and Webpack to remove unused JavaScript files.

6. Optimize Your Website’s Images:

Images can often be a significant source of render-blocking resources on websites, as large image files can take a long time to load. To optimize your website’s images and reduce the amount of time it takes for them to load, you can use image compression and optimization tools.

Tools like TinyPNG and JPEGmini can help you to compress your images without losing their quality. You can also use Lazy Loading, which only loads the images that are visible on the screen and defers the loading of images that are further down the page. This can significantly reduce the amount of time it takes to load your website’s pages, as only the necessary images are loaded this helps Eliminate Render-Blocking Resources.

Optimize Your Website's Images

7. Identify Critical Resources:

The first step to Eliminate Render-Blocking Resources is to identify the critical resources that are required to display the above-the-fold content on your web pages. The above-the-fold content is the portion of the web page that is visible to users without scrolling. By identifying the critical resources, you can prioritize their loading to improve the page’s loading time.

To identify the critical resources, you can use tools like Google PageSpeed Insights or Chrome DevTools. These tools can analyze your website and provide recommendations for improving website speed. They can also identify the resources that are slowing down your website and causing render-blocking issues.

Check more: Minimize Main Thread Work

8. Inline Critical CSS:

Once you have identified the critical resources, to Eliminate Render-Blocking Resources, the next step is to inline the critical CSS. Inlining the critical CSS means embedding the CSS code directly into the HTML code of the web page. By doing this, you can ensure that the CSS code is loaded quickly and doesn’t delay the rendering of the web page.

To inline critical CSS, you can use tools like Critical or Critical Path CSS Generator. These tools can analyze your website and generate the critical CSS code that you can inline into your web pages. By inlining the critical CSS, you can significantly reduce the amount of time it takes to load your website and improve website speed.

9. Monitor Your Website’s Performance:

Once you have taken steps to Eliminate Render-Blocking Resources and optimize your website’s performance, it is essential to monitor your website’s performance regularly. Tools like Google PageSpeed Insights and Chrome DevTools can help you to identify any remaining render-blocking resources and other issues that may be affecting your website’s performance.

Monitoring your website’s performance can also help you to identify any issues that arise over time and to make changes to your website as needed. By regularly monitoring your website’s performance, you can ensure that it continues to run smoothly and provide a great user experience.

Monitor Your Website's Performance

Best practices for Eliminate Render-Blocking Resources:

  1. Prioritize Above-The-Fold Content:

One of the most important steps to Eliminate Render-Blocking Resources is to prioritize above-the-fold content. This means that you should make sure that the content that is visible on the screen without the need for scrolling is loaded as quickly as possible. This content includes things like the header, navigation menu, and hero image.

To achieve this, you should consider using critical CSS. Critical CSS is the CSS that is required to display above-the-fold content. By loading critical CSS inline, you can ensure that it is loaded before any other CSS files are downloaded, which can significantly improve page load times.

Another way to Eliminate Render-Blocking Resources is to prioritize above-the-fold content is to optimize the delivery of your JavaScript files. For example, you can defer the loading of non-critical JavaScript files until after the page has finished rendering. This can help to reduce the amount of time it takes for the page to become interactive.

  1. Test Website Performance After Making Changes:

Once you have implemented changes to Eliminate Render-Blocking Resources, it is important to test your website’s performance to see if the changes have had the desired effect. There are several tools available that can help you do this, including Google PageSpeed Insights and WebPageTest.

These tools can help you identify any remaining Eliminate Render-Blocking Resources and give you recommendations on how to further optimize your website. For example, they may suggest that you compress images or minify CSS files to reduce their file size.

  1. Regularly Review and Update Website:

Even if you are successfully Eliminate Render-Blocking Resources, it is important to regularly review and update your website to ensure that it continues to perform well. This includes removing any unused CSS or JavaScript files and updating any outdated plugins or themes.

You should also consider using a caching plugin to help speed up your website. A caching plugin can store frequently accessed files, such as images and CSS files, on the user’s computer, reducing the need for the browser to download them each time the user visits your website.

Additionally, you should regularly monitor your website’s performance using tools like Google Analytics. This can help you identify any performance issues that may arise and take action to address them.

Conclusion:

In conclusion, Eliminate Render-Blocking Resources is a crucial step in improving website speed and user experience. Render-blocking resources like CSS files, JavaScript files, and fonts can significantly slow down your website’s loading time, which can negatively impact user experience and search engine rankings.

Identifying and optimizing critical resources, as well as deferring non-critical resources, can help Eliminate Render-Blocking Resources and improve website performance. Tools like Google PageSpeed Insights and Chrome DevTools can be used to identify render-blocking resources and provide suggestions for improving website performance.

By taking these steps to Eliminate Render-Blocking Resources, website owners can provide a faster and smoother user experience, which can lead to increased engagement and revenue.

3 Exclusive Easy Ways to Defer Offscreen Images and Videos to Load Pages Faster

Defer Offscreen images or videos are the ones that are positioned outside the screen (viewport) and hence not visible on the screen when a visitor loads a webpage. By indicating the browser not to load the resources currently outside the visible screen area, page load time can be improved.

Loading offscreen resources may affect user experience by downloading data that isn’t immediately required.

GTMetrix

A massive performance boost can be gained as the media elements contain graphics and are commonly the heaviest resources on any page. Smart lazy-loading also called deferred loading is the solution to such problems on a website.

What Will Happen If Offscreen Images Are Not Deferred?

If you don’t defer offscreen pictures, all such assets of your webpage will load at once when one loads your webpage. It will increase page load time, which will eventually lower user experience and performance score. Let’s explain it with an example.

img-8

Let’s imagine your webpage has 15 images and 2 of them are on the front fold. Now if a user visits your website. All 15 images will load at once even if only 2 images are visible and others are below the fold. Your whole HTML structure will block and nothing will render until all the images and other things are completely loaded.

Benefits of Defer Offscreen Images:

Decrease page load time:

Defer Offscreen Images decreases page load time as it loads only the visible images and hence reduces the number of images that need to be loaded. So, your webpage’s HTML structure will not be blocked. Because of this process, the rendering time also decreases.

Saving time and money:

The visitor can only view the generated images if they need them. The user who bounces immediately or doesn’t scroll down will have fewer bytes delivered to their computer. It is literally possible to save money by lazy loading if your CDN provider charges by data transfer and HTTP requests. Those on limited data plans can also save money by lazy loading.

Smart work:

Lazy loading saves computing power and processing time to render a webpage hence saving battery life for hand-held devices such as smartphones or tabs.

Up SEO Ranking:

As the load time decreases and also the site speed increases, the user experience will get better. This will take your website up to the SEO ranking.

Got the point. How to achieve it?

Method 1- use RabbitLoader

The easiest ad best way to defer the loading of resources is to use RabbitLoader on your website. If you are using WordPress, consider trying our free plugin to lazy load images with several other features to score best in Google PageSpeed Insights. Our services can be used for other platforms, including your in-house developed websites with PHP/ASP/NodeJs, etc.

  • Our service can defer pictures used in <img> tags as well as background images by automatically detecting and removing defer offscreen images from the critical rendering path.
  • We can lazy load many other heavies on network media embeds or Iframes such as Google Maps, YouTube/Vimeo videos and load them after the webpage is loaded and rendered.
  • We can lazy load iframes used for lead generation or other marketing forms and make sure they can still be served to visitors as soon as possible
  • Help save your server’s bandwidth or CDN cost as some resources are never loaded if the user doesn’t scroll till that point

I am a geek, suggest me some other ways-

Nice to meet you. We are happy to discuss some of the modern methods we are using internally to best optimize the payload served from our client’s websites. We have discussed in the past how to reduce the image size without losing its quality, and in this post, we are going to focus on various loading techniques to separate out critical and non-critical elements and make the best use of the bandwidth and computation power available on the visitor’s device.

Our research starts from the key idea that only those media elements should be loaded with a high priority which is displayed inside of the viewport. And we know for sure, any such resource requested after TTI (Time to Interactive is the point after which a webpage is capable of reliably responding to user inputs.) is not flagged as a violation in the Lighthouse audit.

Method 2- use “loading” HTML attribute

The <img> tag which is used to embed an image into the document now supports a new attribute called “loading” which tells the browser how the source specified for this element should be loaded. The “loading” attribute is optional and can have two possible values if present-

  • loading = "eager” – If this value is set, the browser loads the image immediately irrespective of the element’s visibility or the position with respect to the viewport
  • loading = "lazy" – The image loading is deferred till the browser thinks that the element is going to be visible soon. Typically it happens when a user scrolls the page and reaches a point precalculated by the browser when the load triggers.

Example-

<img loading="lazy" src="example.webp" alt="image-example" class="img-css-rules">
Defer Offscreen images

Challenges with this approach-

  • For every page, it’s a tedious task to identify pictures appearing above and below the fold and set the appropriate value for the ‘loading’ attribute in advance
  • One size can not fit all. The page may have pictures placed in such a way that on a desktop browser, 6 images appear above the fold, but on a mobile browser, only 3 pictures are appearing on the screen. This attribute can not help you in this situation.
  • You can take the help of JavaScript to set the appropriate values but that may increase the load on the main thread and thus increase the TBT (total blocking time) score of the Lighthouse audit.
  • The feature is not yet supported by some browsers. For a full list of supported browsers with their versions, see the below table.

Browser Compatibility for loading HTML attribute

This feature is now supported by almost all modern browsers except IE, Safari, and Firefox for Android. All Chromium-based browsers may not support it below version 77.

image-lazy-load-support
Image credit –mozilla

Method 3- attach JS listener to elements visibility event

The Intersection Observer API can let your JavaScript listener function know when exactly an element might be entering to viewport or in close proximity. You can then modify the DOM to set the correct source to load the media. This API gives you a superfine control to adjust margins around the viewport to give you buffer time to load the resources without the user observing any broken experience.

user-mouse-scroll

This JavaScript API is used by many plugins along with a fallback or polyfill to lazy load elements on the webpage. You can go on writing it on your own or can pick a plugin like lazysizes and get started quickly.

Example

The below example covers the basic concepts of using this API for an HTML page-

See the Pen
Lazy loading images using IntersectionObserver – example code
by ImageKit.io (@imagekit_io)
on CodePen.

Browser Compatibility for Intersection Observer

This feature is now supported by almost all modern browsers except IE. You can use a polyfill available for Intersection Observer.

interaction-observer-support
Image credit –mozilla

Things to take care of when lazy loading resources

  1. Consider using a placeholder image of small size but similar dimensions to the original image to avoid layout reflow and calculation which is expensive
  2. It’s not a good idea to lazy load images appearing above the fold which should be visible to the user as soon as the page is loaded. This can also impact the CLS score of Core Web Vitals.
  3. Heavy JS functions written to achieve this goal can increase the load on the browser’s main thread and impact the user’s interaction
  4. If a visitor scrolls the page too fast, they may reach a point where the media is still to be loaded. You need the right balance and observe interactions carefully.

For Rabbit Loader users, we have added this as an opt-in feature where iframes and pictures can be routed via our CDN and lazy-loaded in the best possible way across browsers without site owners putting any extra effort. Once enabled, defer offscreen images used in a webpage can be automatically deferred to boost page loading time and improve the speed index.