Css3 100Vh Not Constant in Mobile Browser

CSS3 100vh not constant in mobile browser

Unfortunately this is intentional…

This is a well know issue (at least in safari mobile), which is intentional, as it prevents other problems. Benjamin Poulain replied to a webkit bug:

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 has researched this quite a bit: https://nicolas-hoizey.com/2015/02/viewport-height-is-taller-than-the-visible-part-of-the-document-in-some-mobile-browsers.html

No fix planned

At this point, there is not much you can do except refrain from using viewport height on mobile devices. Chrome changed to this as well in 2016:

• https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/BK0oHURgmJ4
• https://developers.google.com/web/updates/2016/12/url-bar-resizing

CSS 100vh is too tall on mobile due to browser UI

Usually the 100vh height will account for the adjusted height, with is why you'll sometimes see mobile pages go funky when the browser's address bar slides down.

For browsers that don't account for the sliding bar within the vh unit: The height for the address bars will not be constant across the browsers, so I'd advise against appending -50px.

Try setting the height of the page (using javascript) with the window.innerheight property.

function resetHeight(){
    // reset the body height to that of the inner browser
    document.body.style.height = window.innerHeight + "px";
}
// reset the height whenever the window's resized
window.addEventListener("resize", resetHeight);
// called to initially set the height.
resetHeight();

CSS3 100vh not constant in mobile browser

Unfortunately this is intentional…

This is a well know issue (at least in safari mobile), which is intentional, as it prevents other problems. Benjamin Poulain replied to a webkit bug:

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 has researched this quite a bit: https://nicolas-hoizey.com/2015/02/viewport-height-is-taller-than-the-visible-part-of-the-document-in-some-mobile-browsers.html

No fix planned

At this point, there is not much you can do except refrain from using viewport height on mobile devices. Chrome changed to this as well in 2016:

• https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/BK0oHURgmJ4
• https://developers.google.com/web/updates/2016/12/url-bar-resizing

viewport height (100vh) on mobile leads to unwanted scroll

A couple of things.

First the code to set the CSS variable --vh. It needs to be run on the initial and any subsequent load as well as on resize:

function resize() {
  // We execute the same script as before
  let vh = window.innerHeight * 0.01;
  document.documentElement.style.setProperty('--vh', `${vh}px`);
}

window.addEventListener('resize', resize);
window.addEventListener('load', resize);

body {
  height: calc(var(--vh, 1vh) * 100);
}

<body>
</body>

html, body {
    overflow: hidden;
    height: 100%;
}

.centered_layout{
    position: fixed;
    inset: 0;
    overflow: auto;

    display: grid;
    place-items: center;
}

<div class="centered_layout">
    Centered app
</div>