5 Common Page Speed Errors
By Ian on November 20, 2023 in Speed and Functionality
When it comes to optimizing the performance of your website, page speed is a crucial factor. Users expect fast-loading pages, and search engines consider it an important ranking signal. One particular metric that affects page speed is Cumulative Layout Shift (CLS). CLS measures the visual stability of a web page, indicating how much the page layout shifts during the loading process. In this article, we will explore the five most common CLS page speed errors and how to address them.
Images and Video without Dimensions
One of the primary causes of CLS is images and videos that load without predefined dimensions. When the browser doesn’t know the size of these elements in advance, it may render them with default dimensions, causing layout shifts as the actual content loads. To solve this, always specify width and height attributes for images and video elements. By doing so, the browser can allocate the required space for the media, preventing unexpected layout shifts.
Inadequate Font Loading Strategy
Another common culprit behind Cumulative Layout Shift (CLS) issues is an improper font loading strategy. When web fonts are loaded asynchronously, they can disrupt the page’s layout when they finally render. This often occurs because the text initially appears with default system fonts and then suddenly shifts to the specified web font. To tackle this, consider employing a robust font loading strategy. One effective approach is to use the “font-display: swap” CSS property. This instructs the browser to use fallback fonts until the web font is fully loaded, thus minimizing layout shifts and ensuring a smoother user experience.
Dynamic Content Injection
Injecting dynamic content / styles into a page after it has finished loading can significantly impact CLS. If you’re adding content dynamically, ensure that the container elements have fixed dimensions to prevent layout shifts. By assigning a predefined size, you reserve the necessary space, allowing the new content to seamlessly integrate into the layout without causing disruptions.
Use Critical CSS for What’s Seen First
To boost your page’s speed and reduce layout shifts, employ critical CSS. This method involves loading the essential styles needed to display what’s visible on the screen immediately (above-the-fold content) first.
- Identify Key Styles: Pick out the CSS rules necessary for the initial view, like headings, menus, and main content.
- Create a Compact CSS File: Make a separate CSS file containing only these critical styles, keeping it lightweight.
- Load It First: Either include this CSS directly in the HTML, load it asynchronously with JavaScript, ensuring it’s loaded before other styles.
By doing this, you ensure that users see the crucial parts of your page right away, reducing layout shifts and enhancing their experience.
Delayed Loading of Non-Essential JavaScript
Another common factor contributing to Cumulative Layout Shift (CLS) is the delayed loading of non-essential JavaScript. When scripts load too late in the page rendering process, they can disrupt the layout, causing unexpected shifts.
To address this issue, adopt a strategy for managing JavaScript loading. Prioritize essential scripts and load them early in the page’s lifecycle. For non-essential scripts, use asynchronous loading techniques or defer their loading until after the critical content has rendered. By optimizing your JavaScript loading, you can minimize layout shifts and provide a more stable user experience.
Cumulative Layout Shift (CLS) is a critical metric for optimizing your website’s performance. It directly affects user experience and can influence your site’s search engine ranking. By addressing the common CLS errors discussed in this article, you can significantly enhance the visual stability of your web pages. Of course, if you’re not sure how to assess you speed or you need assistance implementing the “fixes, don’t hesitate to reach out. Reach out to us, and our team will be happy to assist you with your options.
