Ad Blocker Detector — Detection Script
Generate a JavaScript snippet to detect if an ad blocker is active using bait element and fetch methods.
How it works
- 1Configure your options above
- 2Click "Generate" — processing happens in your browser
- 3Copy or download the result
What to do next
About Ad Blocker Detector
Ad Blocker Detector is shaped around how people actually use web and productivity utility utilities online: open the page, drop in a file, get the result. Generate a JavaScript snippet to detect if an ad blocker is active using bait element and fetch methods. The interface stays out of the way once the work begins so the engine can use the available CPU and memory for the actual transformation.
Ad Blocker Detector runs on standard browser APIs — an open-source, well-audited engine that performs the web and productivity utility natively in the browser. It accepts the formats listed in the upload area and produces output that opens in any standard web utility viewer. Per-run input is capped at 0 MB.
The right moment to reach for Ad Blocker Detector is when you have a focused web and productivity utility job that fits inside a browser tab. Open the page, drop in the file or paste your input, choose the options that matter, and the tool returns the result.
The browser sandbox isolates the page's JavaScript from the rest of the system, the same way it isolates every other tab you have open. Ad Blocker Detector works inside that sandbox: it reads the file you give it, processes it with standard browser APIs, and writes the result back. Nothing leaves the page's memory unless you choose to download or copy it.
Constraints worth knowing about: inputs are capped at 0 MB to keep memory usage in a sensible range, one input is processed per run, and the tool must be loaded over HTTPS for the in-browser engine to work. These are properties of the architecture.
As a workflow component, Ad Blocker Detector is the part you reach for when a single, well-defined web and productivity utility step needs to happen. It performs that step and returns a standard file you can carry into the next part of your pipeline.
Ad Blocker Detector fits naturally into the workflow of creators experimenting with formats and teachers building resource lists, both of whom typically need a fast result inside the browser. There is no learning curve to budget for: anyone who has used a typical web upload form can complete a run on the first try.
Output handling is intentionally boring: Ad Blocker Detector produces a single output file and triggers your browser's standard "save" behaviour. If you have a default download folder configured, that is where it will land. There is no Favtoo-side history of jobs you have run.
Ad Blocker Detector is honest about scope: it handles a single, well-defined web and productivity utility step. Specialist edge-case work — uncommon formats, very large inputs, or pipelines that need scripting — is what dedicated desktop apps are for. This page handles the common case quickly.
Ad Blocker Detector is structured around the idea that a useful tool should be its own page. Open the page, do the work, close the tab — the page is the entire product. There is no onboarding flow because there is nothing to onboard into.
A few practical tips that experienced users of Ad Blocker Detector pick up over time. First, keep your default browser updated — the engine relies on standard web APIs and newer browser versions are noticeably faster than ones from a few years ago. Second, close other heavy tabs before processing a large input; the engine shares CPU and memory with whatever else is open. Third, if you re-run the same kind of job often, your last-used settings are remembered for the rest of the tab session, so subsequent runs are essentially one click.
Ad Blocker Detector runs as a regular web page, so there is no install step or permission grant before the first run. The page can be audited by viewing the source or by watching the developer-tools Network tab while a job runs.
If the result is not what you expected, the most common causes are easy to check. Confirm the input is under the 0 MB ceiling — files just above the cap fail silently because the engine refuses to allocate the buffer. Confirm the input is one of the supported formats. And if the page itself feels slow, try closing other heavy tabs to free up memory; the engine runs in your browser, so it competes for the same resources as everything else open.
If Ad Blocker Detector solved your problem, sharing the page link with someone who has the same problem is the most useful thing you can do. The catalog grows mostly through word of mouth; visitors arriving through a recommendation tend to be the ones the tool serves best.
How it works
- 1Open Ad Blocker Detector in your browser. The page loads quickly and the tool is ready to use the moment it becomes interactive.
- 2Select the web utility file you want to process — drag-and-drop and the file picker both work.
- 3Pick any non-default settings you need. Most users leave the defaults alone for the first run and only revisit if the result needs tuning.
- 4Hit the run button. standard browser APIs does the work in your browser tab.
- 5Download the result. The file is generated in your browser and saved through your normal download flow.
- 6Repeat the process for additional inputs whenever you need to. The page stays loaded, so subsequent runs are quick.
Common use cases
- Run a one-off check during a meeting without context-switching using Ad Blocker Detector.
- Validate a setting before circulating it to a team.
- Compare two product variations side by side.
- Pull a quick reference number for a status update.
- Audit a marketing page before launch.
- Generate a temporary asset for a social post.
- Create a placeholder image for a wireframe.
- Sanity-check a webhook response while debugging.
- Run a fast accessibility check before publishing.
FAQ
How does detection work?
Two methods: creating a bait element with ad-like CSS classes, and attempting to fetch an ad script URL.
Is this 100% accurate?
No — some blockers may not catch both methods, and false positives are possible.
Is it ethical to detect ad blockers?
Detection itself is neutral — using it to politely ask users to allowlist is common and generally accepted.
Does it block the ad blocker?
No — it only detects presence. Anti-adblock circumvention is a separate and controversial topic.
Which ad blockers are detected?
Most popular blockers including uBlock Origin, AdBlock Plus, and built-in browser blockers.
Private?
Yes — the detection code runs in the browser. The fetch test may be blocked but no data is sent.
Is it safe to use Ad Blocker Detector on confidential files?
Your file is processed inside your browser by standard browser APIs. The engine reads the file's bytes from your tab's memory, computes the result, and writes the result back into the tab. You can confirm what the page does by opening developer tools and watching the Network tab during a run — the requests you see are for the tool's static assets only.
How is Ad Blocker Detector different from desktop apps that do the same thing?
Desktop apps usually have more advanced features but require installation, maintenance and (often) a licence. Paid online tools are convenient but route your file through their servers and gate downloads behind accounts. Ad Blocker Detector sits in between: free, instant, and private, but intentionally narrow in scope. For one-off jobs and the common web and productivity utility operations, it is usually the lowest-friction choice; for highly specialised work, a dedicated app is still the right answer.
Is there a programmatic version of Ad Blocker Detector?
Ad Blocker Detector is a browser-only tool by design and does not expose a hosted API. The reason is the same as the privacy story: there is no Favtoo backend doing the work, so there is no service to call. If you need to script the same transformation, the underlying engine (standard browser APIs) is open-source and can be used directly from your own code.
Why did Ad Blocker Detector reject my input?
Failures usually fall into one of three buckets: the input is in an unsupported format, the input is over the size cap, or the input is structurally malformed (a truncated download, a partial export, or a stream the engine does not recognise). The first two are easy to confirm — check that your file is in a supported format and that it is below 0 MB. For the third, opening the file in its native viewer first is the fastest way to confirm the source is intact.
Does Ad Blocker Detector need an internet connection to run?
Once the page is loaded, Ad Blocker Detector can complete jobs without an active internet connection — the engine is bundled with the page, so there is no per-job network call. The initial page load does require a connection (to fetch the static assets), but after that you can disconnect entirely and the tool will still work. This is a side-effect of the local-first architecture, not a deliberate "offline mode" feature.
Is there a desktop version of Ad Blocker Detector?
No installation is needed. Ad Blocker Detector runs as a normal web page, with no browser extension, no native helper, and no separate desktop client to download. That is partly a privacy choice — extensions can request broad permissions, while a regular page is sandboxed by default — and partly a convenience one: you can use Ad Blocker Detector on any computer you have temporary access to without leaving anything installed on it.
Is Ad Blocker Detector really free?
Ad Blocker Detector is free to use. The processing runs in your browser, which keeps the per-user cost low enough that the tool can be offered openly. The download is the same file the engine produced — you can use it for as many runs as you need.
Does Ad Blocker Detector work with screen readers?
Ad Blocker Detector uses native HTML controls wherever possible, which means keyboard navigation, focus rings, and screen-reader labels work the way the platform expects. The drop zone accepts files via the keyboard-accessible file picker as well as drag-and-drop, and result downloads use standard browser download flows. If you spot an accessibility gap, Favtoo treats it as a bug worth fixing.