100% height on mobile browser using CSS

Question

I'm working on my website and I want it to look really simple on mobile, basically there are just three sections, each one should fit window width and height

<section style="width: 100%; min-height: 100%">
   
</section>

It looks perfect on my computer browser in device mode, but when I open it on my mobile (iPhone), there is a problem with url bar, which gets smaller, as we slide down. On page load, min-height adapts to browser height including the bar, and it doesn't change when bar changes it's dimension. So it doesn't fit the screen anymore. I tried this:

<meta name="viewport" content="height=device-height">

But then, sections are to high, obviously. Probably I could do some workaround in jQuery, but I'd rather not. I hope there is some simple solutions in CSS. Thank you for your time.

Answer 1

This is not as easy as one may think.

Here are some extract from The trick to viewport units on mobile:

Case in point: should the scrollbar be taken into account for the vw unit? What about a site's navigation or page controls — should those count in the calculation? Then there are physical attributes of the devices themselves (hello, notch!) that can't be overlooked.

And then the solution propose:

.my-element {
  height: 100vh; /* Fallback for browsers that do not support Custom Properties */
  height: calc(var(--vh, 1vh) * 100);
}

And some JS:

// 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`);

And some more JS:

// 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`);
});