Page speed is an essential aspect of website performance. The speed at which a page loads can impact user experience, engagement, and search engine rankings. One of the factors that affect page speed is render-blocking resources. In this blog post, we will discuss what render-blocking resources are, why they are problematic, and how to eliminate them to improve page speed.

What are render-blocking resources?

Render-blocking resources are resources that prevent a page from rendering and displaying content until they are fully loaded. These resources can include CSS, JavaScript, and fonts. When a browser encounters a render-blocking resource, it must wait for the resource to load before it can render and display the page’s content.

Why are render-blocking resources problematic?

Render-blocking resources can be problematic because they delay the rendering and display of a page’s content. This delay can negatively impact the user experience and increase bounce rates. According to Google, if a page takes more than three seconds to load, 53% of mobile users will abandon the page. Additionally, Google uses page speed as a ranking factor, which means that slow-loading pages can negatively impact search engine rankings.

How to eliminate render-blocking resources?

There are several ways to eliminate render-blocking resources to improve page speed:

  1. Use async or defer attributes for JavaScript
    Using the async or defer attributes for JavaScript can help eliminate render-blocking resources. The async attribute allows the browser to download the JavaScript file while continuing to load the page’s content. The defer attribute allows the browser to download the JavaScript file while continuing to parse the HTML, and then execute the script after the HTML parsing is complete. This can significantly reduce the amount of time it takes for a page to load.
  2. Inline critical CSS
    Inline critical CSS refers to the practice of including critical CSS directly in the HTML document instead of linking to an external CSS file. By doing this, the critical CSS is loaded first, allowing the browser to render and display the page’s content faster. Non-critical CSS can still be linked in an external file to reduce the overall file size.
  3. Use font-display property for web fonts
    Web fonts can also be render-blocking resources. The font-display property can be used to control how web fonts are displayed while they are loading. The swap value allows the browser to display a fallback font while the web font is loading, which can help reduce the delay in rendering and displaying the page’s content.
  4. Use a content delivery network (CDN)
    A content delivery network (CDN) can help reduce the distance between the user and the server, which can reduce the amount of time it takes for resources to load. Additionally, CDNs can help distribute resources across multiple servers, allowing them to be downloaded faster.

Eliminating render-blocking resources is essential for improving page speed and providing a better user experience. By using async or defer attributes for JavaScript, inline critical CSS, using font-display property for web fonts, and using a content delivery network (CDN), you can reduce the amount of time it takes for resources to load and improve page speed. By improving page speed, you can increase user engagement, reduce bounce rates, and improve search engine rankings.