ChatGPT解决这个技术问题 Extra ChatGPT

iPad Safari scrolling causes HTML elements to disappear and reappear with a delay

I'm currently developing a web application using HTML5 and jQuery for iPad Safari. I'm running into a problem wherein large scroll areas cause the elements that are offscreen to appear after a delay when I scroll down to them.

What I mean by that is, if I have a row of images (or even a div with a gradient) that is offscreen, when I scroll down (or up) to it, the expected behavior is for the element to appear on screen as I am scrolling to it.

However, the element does not appear until I lift my finger off the screen and the scroller finishes all its animations.

This is causing a super noticeable problem for me, making the whole thing look choppy, although it is not. I'm guessing the iPad Safari is trying to do something to save memory. Is there a way in which I can prevent this choppy-ness from happening?

Additionally, what is iPad Safari actually trying to do?

This problem/solution helped me fix an issue with jPanelMenu 1.3 CSS Transforms version, which turned everything on my site invisibie until I added the above snippet.
Using *:not(html) will apply the translate3d to all other aspects of your site and I do not recommend. It will cause images in tabs to disappear as you scroll down, etc, bugs that you might be use to seeing on just your 3d images will now be present in other aspects of your site.
I had a few <svg> elements which were exhibiting similar delayed drawing/rendering. Unfortunately, *:not(html) { ... } led to all sorts of weird behaviors, as @JonathanTonge pointed out might occur. However, selecting only the <svg> elements and using translate3d(0, 0, 0,); seems to have solved my scrolling issues.
Except for very specific use cases, this is garbage. Really messes up layouts that depend on absolute position elements.
Please post answers as answers, not “EDIT”s in your question. I know you like your answer best, and that's fine, but StackOverflow has a Q&A format that works best when the Q's are distinct from the A's.

N
N3R4ZZuRR0

You need to trick the browser to use hardware acceleration more effectively. You can do this with an empty three-dimensional transform:

-webkit-transform: translate3d(0, 0, 0)

Particularly, you'll need this on child elements that have a position:relative; declaration (or, just go all out and do it to all child elements).

It is not a guaranteed fix, but it is fairly successful most of the time.

Hat tip: iOS 5 Native Scrolling–Grins & Gotchas


I tried that as well. Sadly, adding a translate3d is chopping off elements that were being displayed properly before. I also needed hardware acceleration for a couple of objects that were offscreen and had to be animated to "fly in" on screen. I was using jQuery's animate(), which was super slow. I switched over to using hardware acceleration. Although that sped up the animation, it produced erratic results, in the sense that some of the child elements of the parent (animating) div were chopped off. This was not happening when I was using animate().
@Colin Williams you just made my day! :D
Wow, that is horrible but effective. Thank you.
Gold freakin star man! I added it to all my li elements in a scrollable div. Poof. Worked.
P
Peter Mortensen

I was using translate3d before. It produced unwanted results. Basically, it would chop off and not render elements that were offscreen, until I interacted with them. So, basically, in landscape orientation, half of my site that was offscreen was not being shown. This is a iPad web application, owing to which I was in a fix.

Applying translate3d to relatively positioned elements solved the problem for those elements, but other elements stopped rendering, once offscreen. The elements that I couldn't interact with (artwork) would never render again, unless I reloaded the page.

The complete solution:

*:not(html) {
    -webkit-transform: translate3d(0, 0, 0);
}

Now, although this might not be the most "efficient" solution, it was the only one that works. Mobile Safari does not render the elements that are offscreen, or sometimes renders erratically, when using -webkit-overflow-scrolling: touch. Unless a translate3d is applied to all other elements that might go offscreen owing to that scroll, those elements will be chopped off after scrolling.

(This is the complete answer to my question. I had originally marked Colin Williams' answer as the correct answer, as it helped me get to the complete solution. A community member, @Slipp D. Thompson edited my question, after about 2.5 years of me having asked it, and told me I was abusing SO's Q & A format. He also told me to separately post this as the answer. @Colin Williams, thank you! The answer and the article you linked out to gave me a lead to try something with CSS. So, thanks again, and hope this helps some other lost soul. This surely helped me big time!)


Wow. Thanks for this. It saved me a huge amount of headache for my phonegap/cordova app. In my case I had to change *:not(html) to body *
just applying -webkit-transform: translate3d(0, 0, 0); to the problem element worked for me. In my case I was using ScrollMagic
None of this worked for me either. As soon as I scroll down to a certain point, the no-longer-visible stuff above the window gets munged, as well as some elements in the viewport. I notice a very slight but unmistakable "jolt" while it's scrolling after which the elements get hosed. (Ie: smooth--jittery--smooth behavior, like it's hiccuping during scrolling.) This is in on iPad.
BTW I just discovered that on an iPad Air 2, when a specific on-screen element (a navbar, in this case) goes off screen, the device "reloads" that block--only using the large version, not the original medium one that the page loaded with. What the...
In case anyone is experiencing the same weirdness as me--slightly different from what is described on this page--I found that using $(window).width() instead of window.innerWidth in jQuery made all the difference for iOS. Who knows.
P
Peter Mortensen

Targeting all elements but html: *:not(html) caused problems on other elements in my case. It modified the stacking context, causing some z-index to break.

We should better try to target the right element and apply -webkit-transform: translate3d(0,0,0) to it only.

Sometimes the translate3D(0,0,0) doesn't work. We can use the following method, targeting the right element:

@keyframes redraw{
    0% {opacity: 1;}
    100% {opacity: .99;}
}

/* iOS redraw fix */
animation: redraw 1s linear infinite;

I was facing same issue. You can use body * selector instead of *:not(html). It will solve you issue.
Kudos for the suggestion to target the right elements rather than polluting everything with the *
P
Peter Mortensen

When the translate3d doesn't work, try to add perspective. It always works for me

transform: translate3d(0, 0, 0);
-webkit-transform: translate3d(0, 0, 0);
perspective: 1000;
-webkit-perspective: 1000;

Increase Your Site’s Performance with Hardware-Accelerated CSS


holy c$#@ finally a solution for angular/ionic. -webkit-perspective: 1000;
Ahh Saved my day. +1 for you ;)
This made my iOS browser crash.
-webkit-perspective: 1000; did it for me - thank you
P
Peter Mortensen

Adding -webkit-transform: translate3d(0,0,0) to an element statically doesn't work for me.

I apply this property dynamically. For example, when a page is scrolled, I set -webkit-transform: translate3d(0,0,0) on a element. Then after a short delay, I reset this property, that is, -webkit-transform: none This approach seems to work.

Thank you, Colin Williams for pointing me in the right direction.


This hint helped me a lot, since these styles bing some unwanted side effects, I usually want to avoid. So I use touchstart/touchend events to add and remove them. Thanks!
Dynamically applying the style worked well for me. It's a React app so I made a hook that returns the className to apply to the scrolling container based on its children. Whenever the children change, or after the setTimeout has finished, the hook toggles the class between .ios-fix and an empty string so you can apply it with <div className={className}>.
P
Peter Mortensen

I had the same issue with iscroll 4.2.5 on iOS 7. The whole scroll element just disappear.

I've tried to add translate3d(0,0,0) as was suggested here. It has solved the problem, but it disabled the iscroll "snap" effect.

The solution came with giving the "position:relative; z-index:1000;display:block" CSS properties to the whole container that holds the scroll element and there isn't any need to give translate3d to child elements.


I used this technique to solve a similar problem on Android Chrome. Vertical scrolling seemed to perform better than when I tried the translate3d fix. In my case <body> element is what I used for scrolling and a simplified version worked: body { position: relative; z-index: 0; }
P
Peter Mortensen

I had the same issue using an older version of Fancybox.

Upgrading to v3 will solve your problem or you can just add:

html, body {
    -webkit-overflow-scrolling : touch !important;
    overflow: auto !important;
    height: 100% !important;
}

P
Peter Mortensen

At time translate3d may not work. In those cases perspective can be used

transform: translate3d(0, 0, 0);
-webkit-transform: translate3d(0, 0, 0);
perspective: 1000;
-webkit-perspective: 1000;

D
David Notik

I'm pretty darn sure I just solved this with:

overflow-y: auto;

(Presumably just overflow: auto; would work too depending on your needs.)


It did nothing for me whereas the accepted answer did so probably a different scenario
S
Stefan Zurfluh

There are cases where a rotation is applied and/or a Z index is used.

Rotation: An existing declaration of -webkit-transform to rotate an element might not be enough to tackle the appearance problem as well (like -webkit-transform: rotate(-45deg)). In this case you can use -webkit-transform: translateZ(0px) rotateZ(-45deg) as a trick (mind the rotateZ).

Z index: Together with the rotation you might define a positive z-index property, like z-index: 42. The above steps described under "Rotation" were in my case enough to resolve the issue, even with the empty translateZ(0px). I suspect though that the Z index in this case may have caused the disappearing and reappearing in the first place. In any case the z-index: 42 property needs to be kept -- -webkit-transform: translateZ(42px) only is not enough.


P
Peter Mortensen

This is a very common problem faced by developers and that is mainly due to Safari's property of not recreating elements defined as position : fixed.

So either change the position property or some hack needs to be applied as mentioned in other answers.

Issues with position fixed & scrolling on iOS

Change to position fixed on iOS Safari while scrolling


P
Peter Mortensen

In my case (an iOS PhoneGap app), applying translate3d to relative child elements did not resolve the issue. My scrollable element didn't have a set height as it was absolutely positioned and I was defining the top and bottom positions.

Adding a min-height (of 100 pixels) fixed it for me.


P
Peter Mortensen

I faced this problem in a Framework7 and Cordova project. I tried all the solutions above. They did not solve my problem.

In my case, I was using more than 10 CSS animations on the same page with infinite rotation (transform). I had to remove the animations. It is OK now with the lack of some visual features.

If the solutions in other answers do not help you, you may start eliminating some animations.


P
Peter Mortensen

The -webkit-transform: translate3d(0, 0, 0); trick didn't work for me. In my case I had set a parent to:

/* Parent */
height: 100vh;

Changing that to

height: auto;
min-height: 100vh;

solved the issue in case someone else is facing the same situation.


P
Peter Mortensen

In my case, CSS did not fix the issue. I noticed the problem while using jQuery re-render a button.

$("#myButton").html("text")

Try this:

$("#myButton").html("<span>text</span>")