Lazy Loading Ads

Publishers and ad professionals often find themselves in a difficult situation, especially when they deal with a vast amount of information. However, their ultimate goal is to optimize ad performance and boost revenue. Lazy-loading Ads have emerged as a common strategy to achieve this objective. 

Ads, by nature, can be sluggish and difficult to manage. This slowness stems from the fact that each display advertisement functions as a miniature website. So, you must ensure they have their own set of JavaScript, styles, images, and HTML. All of these factors increase the Ads’ speed and execute necessary tracking. 

Balancing the slow nature of Ads with page speed optimization requires a smart technique. Lazy loading stands can help you balance it easily without compromising your ad quality. 

If you are a publisher who seeks methods to enhance your site’s performance, you may have heard about “Lazy Loading” or “Ad Refresh” and its transformative effects on achieving objectives. However, what proves effective for one website may not necessarily yield the same results for another. 

So, how do you achieve the desired outcome using lazy load Ads? We will delve into the concept of lazy loading Ads to help you discern its potential benefits and determine whether it’s a worthwhile implementation for your site.

Concept of Lazy Loading Ads

Lazy loading is a technique used in web development to defer the loading of non-essential resources, such as images, scripts, or content until they are necessary. The concept behind lazy loading is to prioritize the loading of critical resources required to render the initial view of a webpage. That is how it improves page load times and user experience.

When a web page is loaded, all resources referenced in the HTML markup are typically fetched and rendered by the browser. However, this can lead to longer loading times, especially for pages with large content or media assets. Lazy loading addresses this issue by delaying the loading of certain resources until they are visible within the user’s viewport.

For example, consider a webpage with a long article containing multiple images. Instead of loading all images when the page initially loads, lazy loading allows images to load only as the user scrolls down the page and approaches each image’s position. 

You must have seen this effect on most eCommerce websites. This approach reduces the initial page load time, as only the images that are immediately visible to the user are loaded initially, while the rest are loaded dynamically as the user interacts with the page.

Lazy loading is typically implemented using JavaScript, which detects when elements enter the viewport. It then triggers the loading of the corresponding resources. This technique helps optimize resource usage and bandwidth, particularly on devices with limited connectivity or slower internet speeds.

In a similar vein, lazy loading The term “ads” describes a method in which web pages dynamically load ads. Only when you engage with the content will they become apparent. Lazy loading waits for the advertising to load until they are ready to be seen, as opposed to loading them all at once when the page loads.

When Do You Use Lazy Loading Ads?

Lazy-loading Ads are useful when you optimize page load times and improve user experience. Here are some situations when lazy loading Ads may be beneficial:

Long-Scrolling Pages 

Websites with long-scrolling pages, such as news articles, blogs, or product listings, can benefit from lazy loading Ads. By loading Ads as the user scrolls down the page, you ensure that critical content loads quickly, while Ads are loaded progressively. This way Ads can enhance the overall user experience.

Mobile Optimization

Lazy-loading Ads are useful for mobile optimization, where bandwidth and page load times are critical. By delaying the loading of Ads until you reduce the initial page load time. It will lead to faster load times and improved performance, especially on slower mobile networks.

Content-Heavy Websites

Websites with huge content or media assets, such as images, videos, or interactive elements, can benefit from lazy loading Ads. It can prioritize the loading of essential content and defer the loading of Ads until later. This way, you can ensure the users access the core content of the website without delays.

Enhanced User Experience

Lazy-loading Ads contribute to a smoother and more seamless browsing experience for users. By preventing Ads from causing delays or interruptions during the initial page load, you create a more enjoyable user experience. It will also reduce bounce rates and increase engagement.

Ad Viewability and Performance 

Lazy-loading Ads can improve ad viewability and performance. They ensure that Ads are only loaded when they are likely to be viewed by users. Once the users scroll or interact with the page, they will pop up the Ads. It can increase the likelihood of Ad impressions and clicks which ultimately improves ad revenue for advertisers.

Where Can You Apply Lazy Loading Ads?

Publishers and Ad managers can apply lazy loading Ads in various contexts across websites. They can improve performance, user experience, and ad viewability. Here are some common areas where you can implement lazy loading Ads:

  • Interstitial or Overlay Ads: Interstitial or overlay Ads, which appear as full-screen overlays between page transitions or as pop-ups, can benefit from lazy loading. By loading these Ads only when they are triggered by user actions, such as clicking a link or button, you prevent them from interrupting the user experience. 
  • Infinite Scroll or Pagination: Websites with infinite scroll or pagination features can use lazy loading Ads to ensure the dynamic loading of Ads as users navigate through the content. This approach helps maintain a seamless browsing experience while maximizing ad viewability and engagement.
  • Responsive Design: Lazy loading Ads can also help in responsive web design. They can optimize ad delivery based on the user’s device and screen size. Loading Ads selectively based on device capabilities and viewport size ensures that Ads are displayed appropriately and efficiently across different devices and resolutions.
  • Single-Page Applications (SPAs): SPAs, which dynamically load content without full page refreshes, can benefit from lazy loading Ads. They can minimize initial load times and improve performance. They can load Ads asynchronously as users navigate through different sections. It will help you enhance ad viewability and maintain a smooth user experience.

Why Use Lazy Loading Ads?

There are several reasons to use lazy loading Ads in the changing digital landscape:

Improved Page Load Times 

If you prioritize the loading of critical content and delay non-essential elements like Ads, you create a faster and more responsive browsing experience for your audience.

Optimized Ad Viewability 

Lazy loading Ads ensure that Ads are only loaded when the viewers take any action on the page. This way, you increase the likelihood of Ad impressions and clicks.

Bandwidth Conservation 

Lazy-loading Ads help conserve bandwidth, especially on mobile devices or slower internet connections. It will load the Ads only as needed. It can help you reduce the amount of data transferred during the initial page load. The process also leads to lower data usage and improved performance, particularly for users with limited bandwidth or data caps.

Minimized Intrusiveness 

Traditional Ads that load at once can be intrusive and disrupt the user experience. With lazy loading Ads, you can minimize intrusiveness by loading Ads progressively as users scroll or interact with the page. It ensures a smoother and less disruptive browsing experience.

Optimized Revenue Generation 

Despite delaying the loading of Ads, lazy loading can optimize revenue generation in the long run. It can improve page load times and user experience which allows you to increase user engagement and retention. As a result, you get more ad impressions, clicks, and ultimately higher ad revenue over time.

How to Use Lazy Loading Ads?

Implementing lazy loading Ads involves several steps, but it can significantly improve page load times and user experience. Here’s a detailed process on how to use lazy loading Ads:

  1. Identify Ad Placements: Determine the location on your website where you want to place Ads. Common Ad placements include within content, sidebars, headers, footers, or interstitials. Consider user experience, visibility, and ad performance when selecting placements.
  2. Choose a Lazy Loading Method: There are several approaches to implementing lazy loading Ads, depending on your website platform and technical capabilities:
  • JavaScript Libraries: Utilize JavaScript libraries like Intersection Observer or LazyLoad.js to implement lazy loading functionality. These libraries provide pre-built solutions for lazy loading images, iframes, and other elements.
  • Custom JavaScript: Write custom JavaScript code to implement lazy loading functionality tailored to your specific needs. This approach requires coding knowledge and involves manual detection. You must detect when ad elements are within the viewport or about to be interacted with.
  1. Implement Lazy Loading Code: Integrate lazy loading code into your website to trigger the loading of Ads dynamically. It typically involves modifying HTML markup, CSS styles, and JavaScript code as follows:
  • HTML Markup: Update ad placeholders with data attributes or specific classes to identify them for lazy loading.
  • CSS Styles: Apply styles to Ads’ placeholders to ensure they occupy space on the page and maintain layout integrity.
  • JavaScript Code: Write JavaScript code to detect when ad placeholders enter the viewport or are about to be scrolled into view. When triggered, dynamically load ad content, such as ad scripts or iframes, and replace placeholders with loaded Ads.
  • Test and Debug: Test the lazy loading functionality across different devices, browsers, and scenarios to ensure compatibility and effectiveness. Monitor console logs for errors and debug any issues that arise during testing.
  1. Optimize Performance: Monitor and optimize lazy loading performance to ensure fast and efficient ad delivery. Consider factors like load times, ad viewability, user experience, and revenue generation. 
  2. Comply with Ad Policies: Adhere to ad network policies and guidelines when implementing lazy loading Ads to ensure compliance and prevent violations. Be transparent with users about ad loading behavior and provide options for opting out or adjusting ad preferences if applicable.
  3. Monitor and Iterate: Regularly monitor ad performance metrics, user feedback, and website analytics to assess the impact of lazy loading Ads on revenue, user experience, and engagement. Iterate on the implementation as needed to improve results over time.

Pros and Cons of Lazy Loading Ads

Let us discuss the major pros and cons of this method in detail


  • Accelerated Page Load Times: Lazy loading Ads drastically improve page load times by postponing ad loading until they’re likely to be seen by users. This results in quicker initial page load times and a more seamless browsing experience.
  • Elevated User Experience: With faster page load times and reduced clutter, lazy loading Ads enhance the overall user experience. Users can access your website’s core content without delay or interruption caused by ad loading.
  • Maximized Ad Visibility: By dynamically loading Ads as users scroll or interact with the page, lazy loading ensures that Ads are displayed when they’re most likely to be viewed. It boosts ad impressions and clicks, enhancing ad visibility and performance.
  • Preservation of Bandwidth: Lazy loading Ads conserve bandwidth, particularly on mobile devices or slower internet connections. It can lead to improved performance and reduced data usage.


  • Potential Revenue Delay: While lazy loading Ads can improve user experience, they may also delay ad impressions and revenue generation compared to traditional ad loading methods. Ads that are not immediately loaded may result in missed opportunities for ad impressions and clicks.
  • Complex Implementation: Implementing lazy-loading Ads requires technical expertise and can be more complex than traditional ad-loading methods. It involves modifying HTML markup, CSS styles, and JavaScript code to trigger ad loading dynamically based on user interactions.
  • User Expectations: Some users may expect to see Ads immediately upon loading a webpage and may perceive lazy loading as a delay or inconvenience. Balancing ad-loading optimizations with user expectations and preferences is necessary to maintain a positive user experience.
  • Ad Tracking and Measurement: Lazy loading Ads may pose challenges for ad tracking and measurement, as ad impressions and interactions may occur at different times. 

Key Takeaway

Lazy-loading Ads can act as a strategic tool for publishers and ad professionals to optimize ad performance and revenue generation. They can address the challenges associated with sluggish Ads and balance the ad performance with page speed optimization. 

However, you can achieve the best outcomes only when you have the technical knowledge of each component. Lazy loading Ads are emerging as a promising solution to improve page load times and the Ad experts need to be ready with the required skills to give their best in the dynamic digital landscape.

Lauren Aloia

Senior Account Manager, Publisher Development: Newor Media

Lauren is an ad tech expert with a wealth of experience spanning product development, ad operations, and data analysis. She currently works with Newor Media publishers to implement yield optimization strategies that maximize revenue from their programmatic inventory.