JavaScript实现移动端禁止下拉露出网址广告屏蔽技巧

document.body.addEventListener('touchmove', function (e) { e.preventDefault() }, { passive: false })

function stopDown(el) {
    let startX, startY;
    // el是最外层div 
    el.addEventListener("touchstart", (e) => {
        startX = e.changedTouches[0].pageX;
        startY = e.changedTouches[0].pageY;
    })
    el.addEventListener("touchmove", (e) => {
        //获取滑动屏幕时的X,Y
        let endX = e.changedTouches[0].pageX;
        let endY = e.changedTouches[0].pageY;
        //获取滑动距离
        let distanceX = endX - startX;
        let distanceY = endY - startY;
        //判断滑动方向
        if (Math.abs(distanceX) > Math.abs(distanceY) && distanceX > 0) {
            // console.log('往右滑动');
        } else if (Math.abs(distanceX) > Math.abs(distanceY) && distanceX < 0) {
            // console.log('往左滑动');
        } else if (Math.abs(distanceX) < Math.abs(distanceY) && distanceY < 0) {
            // console.log('往上滑动');
        } else if (Math.abs(distanceX) < Math.abs(distanceY) && distanceY > 0) {
            // 核心在这  
            // path 是从触摸点到最外层所有祖先节点的集合,不了解就log看下
            let path = e.path
            let is_scrollTop = false
            // 从触摸点到最外层所有祖先节点 scrollTop不为0就不禁止下拉 为0 就禁止下拉
            for (let dom of path) {
                if (dom.scrollTop) {
                    is_scrollTop = true
                }
            }
            if (!is_scrollTop) {
                e.preventDefault()
                return false
            }
            // console.log('往下滑动');
        } else {
            // console.log('点击未滑动');
        }
    })
}