我有一个很奇怪的问题…在每个浏览器和手机版本中，我都遇到了这种行为:
当你加载页面时，所有的浏览器都有一个顶部菜单(例如显示地址栏)，当你开始滚动页面时，它会向上滑动。
100vh有时只在视口的可见部分计算，所以当浏览器栏向上滑动时，100vh增加(以像素计算)。
所有布局重新油漆和重新调整，因为尺寸已经改变
对用户体验有不好的跳跃效果
如何避免这个问题?当我第一次听说viewport-height时，我很兴奋，我认为我可以使用它来固定高度块，而不是使用javascript，但现在我认为唯一的方法实际上是javascript与一些调整大小事件…
您可以在:示例站点看到问题
有人能帮助我/建议一个CSS解决方案吗?
简单测试代码:
/* maybe i can track the issue whe it occours... */
$(function(){
var resized = -1;
$(window).resize(function(){
$('#currenth').val( $('.vhbox').eq(1).height() );
if (++resized) $('#currenth').css('background:#00c');
})
.resize();
})
*{ margin:0; padding:0; }
/*
this is the box which should keep constant the height...
min-height to allow content to be taller than viewport if too much text
*/
.vhbox{
min-height:100vh;
position:relative;
}
.vhbox .t{
display:table;
position:relative;
width:100%;
height:100vh;
}
.vhbox .c{
height:100%;
display:table-cell;
vertical-align:middle;
text-align:center;
}
<div class="vhbox" style="background-color:#c00">
<div class="t"><div class="c">
this div height should be 100% of viewport and keep this height when scrolling page
<br>
<!-- this input highlight if resize event is fired -->
<input type="text" id="currenth">
</div></div>
</div>
<div class="vhbox" style="background-color:#0c0">
<div class="t"><div class="c">
this div height should be 100% of viewport and keep this height when scrolling page
</div></div>
</div>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
不幸的是，这是故意的……
这是一个众所周知的问题(至少在safari mobile中)，这是故意的，因为它可以防止其他问题。Benjamin Poulain回复了一个webkit漏洞:
This is completely intentional. It took quite a bit of work on our part to achieve this effect. :)
The base problem is this: the visible area changes dynamically as you scroll. If we update the CSS viewport height accordingly, we need to update the layout during the scroll. Not only that looks like shit, but doing that at 60 FPS is practically impossible in most pages (60 FPS is the baseline framerate on iOS).
It is hard to show you the “looks like shit” part, but imagine as you scroll, the contents moves and what you want on screen is continuously shifting.
Dynamically updating the height was not working, we had a few choices: drop viewport units on iOS, match the document size like before iOS 8, use the small view size, use the large view size.
From the data we had, using the larger view size was the best compromise. Most website using viewport units were looking great most of the time.
Nicolas Hoizey对此做了很多研究:https://nicolas-hoizey.com/2015/02/viewport-height-is-taller-than-the-visible-part-of-the-document-in-some-mobile-browsers.html
没有修复计划
在这一点上，除了避免在移动设备上使用视口高度之外，你没有什么可以做的。Chrome在2016年也变成了这样:
https://groups.google.com/a/chromium.org/forum/ !主题/ blink-dev / BK0oHURgmJ4
https://developers.google.com/web/updates/2016/12/url-bar-resizing
看看这个答案:https://css-tricks.com/the-trick-to-viewport-units-on-mobile/
// First we get the viewport height and we multiple it by 1% to get a value for a vh unit
let vh = window.innerHeight * 0.01;
// Then we set the value in the --vh custom property to the root of the document
document.documentElement.style.setProperty('--vh', `${vh}px`);
// We listen to the resize event
window.addEventListener('resize', () => {
// We execute the same script as before
let vh = window.innerHeight * 0.01;
document.documentElement.style.setProperty('--vh', `${vh}px`);
});
body {
background-color: #333;
}
.module {
height: 100vh; /* Use vh as a fallback for browsers that do not support Custom Properties */
height: calc(var(--vh, 1vh) * 100);
margin: 0 auto;
max-width: 30%;
}
.module__item {
align-items: center;
display: flex;
height: 20%;
justify-content: center;
}
.module__item:nth-child(odd) {
background-color: #fff;
color: #F73859;
}
.module__item:nth-child(even) {
background-color: #F73859;
color: #F1D08A;
}
<div class="module">
<div class="module__item">20%</div>
<div class="module__item">40%</div>
<div class="module__item">60%</div>
<div class="module__item">80%</div>
<div class="module__item">100%</div>
</div>
因为我是新人，我不能对其他答案发表评论。
如果有人正在寻找一个答案，使这个工作(可以使用javascript -似乎需要使这个工作的时刻)，这种方法对我来说非常有效，它也说明了移动方向的变化。我使用Jquery的示例代码，但应该是可行的与vanillaJS。
-首先，我使用一个脚本来检测设备是触摸还是悬停。的例子:
if ("ontouchstart" in document.documentElement) {
document.body.classList.add('touch-device');
} else {
document.body.classList.add('hover-device');
}
这将根据稍后用于高度脚本的设备类型(悬停或触摸)向body元素添加类。
-接下来使用这段代码来设置设备在负载和方向变化时的高度:
if (jQuery('body').hasClass("touch-device")) {
//Loading height on touch-device
function calcFullHeight() {
jQuery('.hero-section').css("height", $(window).height());
}
(function($) {
calcFullHeight();
jQuery(window).on('orientationchange', function() {
// 500ms timeout for getting the correct height after orientation change
setTimeout(function() {
calcFullHeight();
}, 500);
});
})(jQuery);
} else {
jQuery('.hero-section').css("height", "100vh");
}
-Timeout设置，以便设备在方向改变时正确计算新的高度。如果没有超时，根据我的经验，高度是不正确的。500毫秒可能有点过分，但对我来说很有效。
如果浏览器覆盖CSS的100vh，则-100vh在hover-devices上是一个备用选项。
React用useEffect和useState挂钩解决方案
function App() {
const [vh, setVh] = useState(window.innerHeight);
useEffect(() => {
const updateVh = () => {
setVh(window.innerHeight);
};
window.addEventListener('resize', updateVh);
return () => window.removeEventListener('resize', updateVh);
}, []);
return (
<div style={{ height: vh }}>
{vh} px
</div>
);
}
演示:https://jsfiddle.net/poooow/k570nfd9/
