javascript - iOS 10 Safari : Prevent scrolling behind a fixed overlay and maintain scroll position

在显示固定位置覆盖时，我无法阻止主体内容滚动。类似的问题已被问过很多次，但所有以前有效的技术似乎都不适用于 iOS 10 中的 Safari。这似乎是最近的一个问题。

一些注意事项:

如果我将 html 和 body 都设置为 overflow: hidden，我可以禁用滚动，但是这会使正文内容滚动到顶部.
如果叠加层中的内容足够长，可以滚动，则主页内容的滚动会被正确禁用。如果overlay中的内容不够长导致滚动，可以滚动主页面内容。
我包含了一个来自 https://blog.christoffer.online/2015-06-10-six-things-i-learnt-about-ios-rubberband-overflow-scrolling/ 的 javascript 函数在显示叠加层时禁用 touchmove。这以前有效，但不再有效。

这是完整的 HTML 源代码:

<!doctype html>
<html>
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.2.4/jquery.min.js"></script>
    <style type="text/css">
        html, body {
            width: 100%;
            height: 100%;
            margin: 0;
            padding: 0;
        }
        body {
            font-family: arial;
        }
        #overlay {
            display: none;
            position: fixed;
            z-index: 9999;
            left: 0;
            right: 0;
            top: 0;
            bottom: 0;
            overflow: scroll;
            color: #fff;
            background: rgba(0, 0, 0, 0.5);
        }
        #overlay span {
            position: absolute;
            display: block;
            right: 10px;
            top: 10px;
            font-weight: bold;
            font-size: 44px;
            cursor: pointer;
        }
        #overlay p {
            display: block;
            padding: 100px;
            font-size: 36px;
        }
        #page {
            width: 100%;
            height: 100%;
        }
        a {
            font-weight: bold;
            color: blue;
        }
    </style>
    <script>
        $(function() {
            $('a').click(function(e) {
                e.preventDefault();
                $('body').css('overflow', 'hidden');
                $('#page').addClass('disable-scrolling'); // for touchmove technique below

                $('#overlay').fadeIn();
            });
            $('#overlay span').click(function() {
                $('body').css('overflow', 'auto');
                $('#page').removeClass('disable-scrolling'); // for touchmove technique below

                $('#overlay').fadeOut();
            });
        });

        /* Technique from http://blog.christoffer.me/six-things-i-learnt-about-ios-safaris-rubber-band-scrolling/ */
        document.ontouchmove = function ( event ) {
            var isTouchMoveAllowed = true, target = event.target;
            while ( target !== null ) {
                if ( target.classList && target.classList.contains( 'disable-scrolling' ) ) {
                    isTouchMoveAllowed = false;
                    break;
                }
                target = target.parentNode;
            }
            if ( !isTouchMoveAllowed ) {
                event.preventDefault();
            }
        };
    </script>
</head>

<body>
    <div id="overlay">
        <span>&times;</span>
        <p>fixed popover</p>
    </div>

    <div id="page">
        <strong>this is the top</strong><br>
        lots of scrollable content<br>
        asdfasdf<br>
        lots of scrollable content<br>
        asdfasdf<br>
        lots of scrollable content<br>
        asdfasdf<br>
        lots of scrollable content<br>
        asdfasdf<br>
        lots of scrollable content<br>
        asdfasdf<br>
        lots of scrollable content<br>
        asdfasdf<br>
        lots of scrollable content<br>
        asdfasdf<br>
        lots of scrollable content<br>
        asdfasdf<br>
        lots of scrollable content<br>
        asdfasdf<br>
        lots of scrollable content<br>
        asdfasdf<br>
        lots of scrollable content<br>
        asdfasdf<br>
        lots of scrollable content<br>
        asdfasdf<br>
        lots of scrollable content<br>
        asdfasdf<br>
        lots of scrollable content<br>
        asdfasdf<br>
        lots of scrollable content<br>
        asdfasdf<br>
        lots of scrollable content<br>
        asdfasdf<br>
        lots of scrollable content<br>
        asdfasdf<br>
        lots of scrollable content<br>
        asdfasdf<br>
        lots of scrollable content<br>
        asdfasdf<br>
        lots of scrollable content<br>
        asdfasdf<br>
        <br>
        <div><a href="#">Show Popover</a></div>
        <br>
        <br>

    </div>

</body>

</html>

最佳答案

将 -webkit-overflow-scrolling: touch; 添加到 #overlay 元素。

然后在 body 标签的末尾添加这段 JavaScript 代码:

(function () {
  var _overlay = document.getElementById('overlay');
  var _clientY = null; // remember Y position on touch start

  _overlay.addEventListener('touchstart', function (event) {
    if (event.targetTouches.length === 1) {
      // detect single touch
      _clientY = event.targetTouches[0].clientY;
    }
  }, false);

  _overlay.addEventListener('touchmove', function (event) {
    if (event.targetTouches.length === 1) {
      // detect single touch
      disableRubberBand(event);
    }
  }, false);

  function disableRubberBand(event) {
    var clientY = event.targetTouches[0].clientY - _clientY;

    if (_overlay.scrollTop === 0 && clientY > 0) {
      // element is at the top of its scroll
      event.preventDefault();
    }

    if (isOverlayTotallyScrolled() && clientY < 0) {
      //element is at the top of its scroll
      event.preventDefault();
    }
  }

  function isOverlayTotallyScrolled() {
    // https://developer.mozilla.org/en-US/docs/Web/API/Element/scrollHeight#Problems_and_solutions
    return _overlay.scrollHeight - _overlay.scrollTop <= _overlay.clientHeight;
  }
}())

关于javascript - iOS 10 Safari : Prevent scrolling behind a fixed overlay and maintain scroll position，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/41594997/

javascript - iOS 10 Safari : Prevent scrolling behind a fixed overlay and maintain scroll position

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