https://static.beyondmenu.com/beyondmenu/js/BMBodyScrollLock.js?2026092404

1function BMBodyScrollLock() {
2    var _body = document.querySelector('body');
3    var _scrollPosition = 0;
4
5    var _initialWindowInnerHeight = 0;
6
7
8    var bodyLockPosition = 'fixed';
9    try {
10        var ua = window.navigator.userAgent;
11        if (ua.includes('iPhone')) {
12            var m = ua.match(/Version\/(?<ver>[0-9\.]+)/);
13            var version = parseFloat(m.groups.ver);
14            if (!isNaN(version) && version < 16) {
15                bodyLockPosition = 'absolute';
16            }
17        }
18    }
19    catch (e) { }
20
21
22    window.BMBodyScrollLock_LockCounter = window.BMBodyScrollLock_LockCounter || 0;
23
24    this.lock = function () {
25        document.addEventListener('touchmove', onTouchMove);
26
27        window.BMBodyScrollLock_LockCounter++;
28
29        _scrollPosition = window.pageYOffset;
30        _body.style.overflow = 'hidden';
31        _body.style.position = bodyLockPosition;
32        _body.style.top = '-' + _scrollPosition + 'px';
33        _body.style.width = '100%';
34
35        _initialWindowInnerHeight = window.innerHeight;
36    };
37
38    this.unlock = function () {
39        document.removeEventListener('touchmove', onTouchMove);
40
41        window.BMBodyScrollLock_LockCounter--;
42        if (window.BMBodyScrollLock_LockCounter > 0) {
43            return;
44        }
45
46        _body.style.removeProperty('overflow');
47        _body.style.removeProperty('position');
48        _body.style.removeProperty('top');
49        _body.style.removeProperty('width');
50        window.scrollTo(0, _scrollPosition);
51    };
52
53    // https://stackoverflow.com/a/50024226  <- scrollTop idea
54    function onTouchMove() {
55        if (window.innerHeight !== _initialWindowInnerHeight) {
56            // keyboard shown (probably)
57            return;
58        }
59
60        _body.scrollTop = 0;
61    }
62}