https://www.paketda.de/detect-ab.js

1var DetectAb = function (callback, extended) {
2    const bait = document.createElement('div');
3    bait.innerHTML = ' ';
4    bait.className = 'ad-wrapper ad-box';
5    bait.setAttribute('aria-hidden', 'true');
6    bait.style.position = 'fixed';
7    bait.style.top = '200%';
8    document.body.appendChild(bait);
9    window.setTimeout(() => {
10        if (!!bait && (bait.offsetHeight === 0 || window.getComputedStyle(bait)?.display === 'none')) {
11            callback(true, 1);
12        } else {
13            if (extended) {
14                fetch('https://www3.doubleclick.net', {
15                    method: 'HEAD',
16                    mode: 'no-cors',
17                    cache: 'no-store',
18                }).catch(() => {
19                }).then((r) => {
20                    r ? callback(false, 0) : callback(true, 2);
21                });
22            } else {
23                callback(false, 0)
24            }
25        }
26        bait.remove();
27    }, 200);
28}