On the Radar: How Websites Detect Ad Blockers

Ad blocker detection serves as the initial step in addressing the challenges posed by ad blockers, functioning as an essential technological component that prompts a suitable response. Once an ad blocker is identified, websites may implement various measures, including displaying educational messages, imposing paywalls, or even reinserting ads. While the overarching goal of this technology is to alleviate the impact of ad blockers, a more detailed examination reveals specific reasons for detecting ad blockers across different industries.

Technology detecting an ad blocker


JavaScript Detection

Websites commonly utilise JavaScript to dynamically manage and load ad content. The interference caused by ad blockers in the execution of these JavaScript functions is a key detection point. Specialized scripts are often implemented to monitor the loading of ad-related scripts or events triggered by ads. The absence of these anticipated JavaScript executions serves as an indicative signal.

CSS Inspection

The styling of ad elements, defined in Cascading Style Sheets (CSS), becomes a focal point for detection. Websites scrutinize the applied styles to these elements to determine if they are being obstructed. The absence or incompleteness of expected styles for ad-related components is an indication that an ad blocker is hindering the loading of these styles and, consequently, the display of ads.

Placeholder Detection

Ad blockers commonly replace ad spaces with blank or placeholder elements as a visual indicator of blocked content. Websites analyse the HTML structure of their pages to detect the presence of these placeholders. Recognizing these placeholders is evidence of ad blocking, prompting websites to take responsive measures.

Timeouts and Fallbacks

Websites implement timeouts for the loading of ad-related elements, triggering a detection mechanism if they don’t load within the specified time. Additionally, fallback mechanisms are incorporated to display alternative content when ads are not loaded. These visual cues serve as indirect indicators that an ad blocker may be active, encouraging users to consider disabling it for an optimal browsing experience.

Ads timing out

The Purpose of Ad Blocker Detection

Publishers optimize ad blocker detection tools to protect their ad revenue. Publishers can identify readers using ad blockers and deploy a range of potential solutions, aiming either to showcase ads or encourage users to disable their ad blockers. This will allow for funding to be reinvested into Journalism, as the accumulation of ad revenue is a partially due to enticing articles.

Ad blockers can mask certain data that may be required to access websites, such as geolocation. Websites and businesses operating in specific jurisdictions or adhering to certain laws may find it necessary to adopt ad blocker detection technology. This adoption helps mitigate the risk of fines and charges associated with a particular demographic gaining access to content they shouldn’t.

In certain cases, prominent online retailers recognise the need for ad blocker detection technology. This recognition stems from the fact that crucial analytics may be concealed by ad blockers. The identification of any ad blocker software and the subsequent activation of a response enable the provision of more personalized product suggestions to customers, contributing to a higher conversion rate for the online retailer.

Online retailer using technology to detect ad blockers

B2’s Ad Blocker Detection Solution

In conclusion, our Analytics solution stands at the forefront of ad blocker detection, showcasing unparalleled proficiency in identifying various types, including domain ad blockers and CSS ad blockers. With cutting-edge technology, our system goes beyond mere detection, offering in-depth reports that not only categorize the type of ad blocker but also pinpoint the user’s origin. This comprehensive approach empowers publishing businesses that rely on advertising revenues with valuable insights, enabling them to adapt strategies and optimize their online presence effectively. Embracing our B2 Analytics solution ensures a proactive stance in addressing ad blocker challenges, fostering a more informed and strategic approach. B2 Analytics is free and easy to deploy, sign up by clicking on the top right corner of our website.

Please contact the B2 team at info@b2.ai if you wish to learn more.