CSS/JS Gradient-style opacity to fade out content - css

I'm wondering if there's a way to fade out (like a gradient) the opacity of an iframe and the content inside it. It's difficult to explain so a common example would be at the bottom of notification centre on Mountain Lion or iOs.
The whole idea is that when a user scrolls down (in an iframe) the content "fades out" at the bottom and it doesn't cut off with a straight line.
Not sure if this is possible with CSS or Javascript.
Any help is greatly appreciated. Thanks

If I've understood you correctly, you want something like this:
https://dl.dropbox.com/u/73603348/fadeout.html
What I've done in the past is create an overlay element at the bottom of the scrolling content. Pretty simple.
The markup:
<div class="content">
<div class="container">
[ content here ]
</div>
<div class="fader"></div>
</div>
The style:
.content {
width: 600px;
background: #fff;
margin: 50px auto 0;
overflow: auto;
position: relative;
}
.container {
height: 500px;
overflow: auto;
padding: 10px;
background: #ccc;
}
.fader {
position: absolute;
content: '';
bottom: 0;
left: 0;
right: 0;
height: 100px;
background: -webkit-linear-gradient(top, rgba(255,255,255,0), #fff);
}

Just in case you don't want to load the whole jQuery library, you can write your own function to do the fadeout. Here's my own try to write such a function:
var ifrm = document.getElementById("your_frame"); //find your frame
function fadeOut(var duration) { //duration: how many millseconds you want the effect to take
var step = 10 / duration; //step is how much the opacity will change each 10 milliseconds
var curOpacity = 1; //at first the iframe is fully opaque.
function animate() {
if(curOpacity < step) {
ifrm.style.opacity = 0; //we're done
return;
}
ifrm.style.opacity = curOpacity;
curOpacity -= step;
setTimeout(animate, 10); //wait 10 millseconds and move to next step of animation
}
animate();
}
So suppose you want to fadeout for 1 second, then the initial fadeOut function call would be: fadeOut(1000);.
Again, I hope that helped you.

You can use jQuery. Example on how to fade out an element:
$("#your_iframe_id").fadeOut();
More details on how to use fadeOut: jQuery API reference about fadeOut.

Related

How to go about adding a sliding animation for a toggle button?

I have a toggle bar element I am working on and currently I have it working correctly to style the toggled button, but I want more animation.
The idea is to have the curent active button slide to whichever button is newly active. So visually the only thing I would be adding to the current code is the slide animation.
How to do that exactly is where I'm getting stuck. Now the active element isn't just getting a background and some styles, but a floating/sliding box will be needed (I think)
I don't want anyone to impliment it for me, but I am having trouble thinking of how to impliment it. Do I do something with a pseudoelements?
How do I make sure that the white button background element is as wide as the word it needs to be behind?
This is more or less a general CSS question, but I am not sure how to even start this process.
If anyone has any advice or tricks on how to make this work or just pointing me in the right direction, I would greatly appreciate it! Cheers!
This is what I've built so far in CodeSandbox
You could 'create a gap' for the white block to travel in so it is behind the text but in front of the backgrounds by putting the background colors onto the elements using pseudo elements with lower z index.
On click of a button you can look at the previously clicked button and work out how far the white block has to move to get to the current button, and also how its width has to change.
In this snippet the 'white block' is in fact a pseudo element on the currently clicked button. This makes it easy to work out its final resting place which is directly under the currently clicked button.
const buttons = document.querySelectorAll('button');
function clicked(e) {
const el = e.target;
const prevEl = document.querySelector('button.animate');
const x = (prevEl == null) ? '0%' : (prevEl.getBoundingClientRect().x - el.getBoundingClientRect().x) + 'px';
const w2 = window.getComputedStyle(el).width;
const w1 = (prevEl == null) ? 0 : window.getComputedStyle(prevEl).width;
buttons.forEach(button => {
button.classList.remove('animate');
});
el.style.setProperty('--x', x);
el.style.setProperty('--w1', w1);
el.style.setProperty('--w2', '100%');
el.classList.add('animate');
}
buttons.forEach(button => {
button.addEventListener('click', clicked);
}
);
nav {
display: inline-block;
position: relative;
}
nav::before {
content: '';
position: absolute;
background-color: gold;
width: 100%;
height: 100%;
left: 0 top: 0;
z-index: -3;
}
button {
margin: 2vmin;
background-color: transparent;
position: relative;
}
button::before {
content: '';
position: absolute;
width: 100%;
height: 100%;
top: 0;
left: 0;
background-color: brown;
z-index: -2;
}
button.animate::after {
content: '';
position: absolute;
background-color: white;
width: 100%;
height: 100%;
animation-name: move;
animation-duration: 3s;
animation-fill-mode: forwards;
top: 0;
left: 0;
z-index: -1;
}
#keyframes move {
0% {
transform: translateX(var(--x));
width: var(--w1);
}
100% {
transform: translateX(0);
width: var(--w2);
}
}
#keyframes animate {
0% {}
100% {
background-color: white;
}
}
<nav>
<button>AAAA</button>
<button>AA</button>
<button>AAAAAA</button>
<button>A</button>
</nav>
If you want to do it from scratch, and have the ability to control the position of the white box relative to the yellow box (position: relative or absolute), you could hardcode it by creating a function that takes the desired box coordinate, checks if the white box is in the correct place, and if not moves it x px in the right direction, then calls itself recursively with a timeout.
Essentially, move it a little bit every few milliseconds until it gets to the right spot. one move every (1000/24)ms or less should make it look fluid.
As for the size, you could either hardcode that and same idea, or make a function that finds the correct size based on the given text.

set a loading animation with a-frame

I am using a-frame to load panorama photo with the sample code below. It shows a white screen while the photo is being loaded, and it lasts a few seconds, which create a bad user experience. I want to add a loading animation while the photo is being loaded, but cannot find any useful guides. Could anyone help?
<a-scene>
<a-assets>
<img id="sky" src="sky.png">
</a-assets>
<a-sky src="#sky"></a-sky>
</a-scene>
I think aframe 8 will have a built in loading screen. In the meantime here's how I currently tackle it for aframe scenes exported from Ottifox:
First before the a-scene tag and after the start of the body I have this markup:
<div id="splash">
<div class="loading"></div>
</div>
Then in a css file:
#splash {
position: absolute;
display: flex;
align-items: center;
justify-content: center;
top: 0;
bottom: 0;
left: 0;
right: 0;
width: 200px;
height: 200px;
margin: auto;
}
#keyframes spin {
0% {
transform: rotate(0deg);
}
100% {
transform: rotate(360deg);
}
}
.loading {
width: 24px;
height: 24px;
border-radius: 50%;
border: 0.25rem solid rgba(255, 255, 255, 0.2);
border-top-color: white;
animation: spin 1s infinite linear;
}
Finally in main.js
document.addEventListener('DOMContentLoaded', function() {
var scene = document.querySelector('a-scene');
var splash = document.querySelector('#splash');
scene.addEventListener('loaded', function (e) {
splash.style.display = 'none';
});
});
You can view source on the example here, to see it all together:
http://ottifox.com/examples/space/index.html
I can point you in the right direction. Generally speaking; first create something to be shown while everything loads; then after it loads hide it, or do whatever you wish.
For example create a fullscreen div with large z-index, it could show some loader animation for example. Then use javascript - either normal way, or the A-Frame recommended way (build a component for it) - to hide the div.
window.onload = function() {
/* hide loading div */
}
window.onload event is fired after entire page is loaded, including images - which is exactly what you need.
I just built out a pretty in depth load screen replacement for a-frame. You can see the code and demo here: https://glitch.com/edit/#!/a-load-screen
I handle a lot there, but the short version is:
make a full screen div, style as you like, and use z-index to put it on top of the a-scene element
add a listener to document.querySelector('a-scene') for renderstart
aframe will fire that when all the stuff from a-assets as has loaded (or timed out), so you don't need to add custom handling for the various kinds of assets you'll see there
A small code snippet to get you started:
scene.addEventListener('renderstart', (function onAframeRenderStart() {
let haveRun = false;
return () => {
console.warn("RENDER START")
if (haveRun) return;
haveRun = true;
setTimeout(() => {
document.querySelector('.load-div').classList.add('hide-loader');
document.querySelector(".load-div").style.display = "none"
}, 2500)
}
})());

avoid automatic jump to bottom on page with iframe video

I have a video showing on a page like this
<div class="embed-responsive embed-responsive-16by9">
<iframe class="embed-responsive-item" src="{{skin url="video/hande.mp4"}}"></iframe>
</div>
but when loading the page on tablet / mobile the page automatically jumps to the bottom where the video is. I tried adding something like this
<iframe style="display: none;" onload="this.style.display='block';" href="..."></iframe>
following from this question iframe on the page bottom: avoid automatic scroll of the page but the suggestions on there don't work for me.
Can anyone point me in the right direction? Thank you
UPDATE
The OP has found an acceptable solution by utilizing scrollTo:
<script type="text/javascript">
// <![CDATA[ window.onload = function(){ window.scrollTo(0,0); }// ]]>
</script>
which seems to work, there's a bit of a delay though so its not great but so far its the only thing that seems to have worked.
So to add to OP's solution, try:
<script>
// <![CDATA[ document.addEventListener("DOMContentLoaded", function(){ window.scrollTo(0,0); }, false )// ]]>
</script>
Using window.onload means your function will be called after everything else has loaded; DOM, images, script, etc.
Using DOMContentLoaded means your function will be called after the DOM has loaded (which means after any iframes have loaded, which is usually the slowest part of the DOM content). What it doesn't wait for is script, so make sure you place the YouTube script before this line. There are exceptions of course see ARTICLE
UPDATE
It seems that the focus event could be the culprit so what you can do is offer the browser to focus on something else.
Create a temporary transparent input while page is loading.
When the page is fully loaded, use a callback to remove the input.
Forgot to actually update the snippet...so it's added now.
Try this snippet below. View in 'Full Page'. You have to scroll down to the bottom and to your right, because it ain't gonna scroll without help.
document.addEventListener('DOMContentLoaded', init, false);
window.load = function() {
var fpt = document.querySelector('.focalPoint');
fpt.parentNode.removeChild(fpt);
}
function init() {
var fpt = document.createElement('input');
document.body.appendChild(fpt);
fpt.classList.add('focalPoint');
if (fpt != document.activeElement) {
fpt.focus();
}
}
.box {
width: 50vw;
/* Arbitrary */
}
.vidWrap {
position: relative;
/* Anchor the iframe's parent */
padding-bottom: 56%;
/* This is for AR 16:9 (ie. wide screen) videos */
padding-top: 20px;
/* Offset to padding-bottom */
height: 0;
/* Makes a tight 'seal' */
overflow-y: hidden;
/* Ensures that edges aren't breached */
overflow-x: hidden;
/* As above */
-webkit-overflow-scrolling: touch;
/* For iOS7 ... not so sure about iOS8 or iOS9 */
bottom: -50vw;
/* Arbitrary. */
left: 50vw;
/* Arbitrary */
}
.vid {
overflow-x: hidden;
/* See above */
overflow-y: hidden;
/* As above */
height: 100%;
/* stretched to the edge of parent */
width: 100%;
/* As above */
position: absolute;
/* Allows control within the parent */
/* These coords will stretch the iframe seemlessly to parent's edges */
top: 0;
left: 0;
right: 0;
bottom: 0;
}
.focalPoint {
visibility: hidden;
opacity: 0;
line-height: 0;
font-size: 0;
border: 0;
outline: 0;
position: fixed;
top: 0;
left: 0;
z-index: 9999;
}
<section class="box">
<div class="vidWrap">
<iframe id="vid1" class="vid" src="http://media6000.dropshots.com/photos/1381926/20170326/023642.mp4" frameborder="0" scrolling="no" height="100%" width="100%" allowfullscreen></iframe>
</div>
</section>

CSS: Change Cursor over background-image

I have a background image as part of a body class in CSS:
body.soon1 {
background-color: white;
background-image: url(soon1a.png);
background-position: center;
background-repeat: no-repeat;
}
Then later on I have a javascript function that will change the body class.
The reason I have the image in the background is that when the script activates, the background-color and the background-image will both change at exactly the same time and you can't select the image.
Is it possible that I could change the cursor type only while hovering over the background-image? I understand I can put
cursor: pointer;
in the body styles, but this makes the cursor appear over the entire page.
You can view the live page, currently, where the background changes when you click anywhere on the page.
Edit: I've got something that works for me now. I added a centered div with nothing in it:
div.clickme {
width:300px;
height:400px;
position:absolute;
left:50%;
top:50%;
margin:-150px 0 0 -200px;
cursor: pointer;
}
This works for me because I can set my own arbitrary area, but if anybody has a better solution, let me know.
There's really no compelling reason to make the image a background image. You would be better served by putting the image in two wrappers (required to guarantee absolute centering vertically and horizontally regardless of viewport).
You could extend your array by populating it with objects, so that it can hold possible values for the image and the body style. This way, you can use the same method (cycle through the array) to pick out all of the changes you want, even if you wanted to add other changes later.
Also, while web browsers are rather lenient with standards, it really is trivial to conform to the simple HTML 5 requirements and still keep the functionality.
Lastly, I strongly encourage you to avoid what I call "hipster coding". While it's fun to name functions, variables, et al with obscure names to delight the few that check the source code, it makes for needlessly obtuse language and lower maintainability. In short, it's a bad practice, even if you are the only maintainer.
Observe a new version of your source based on these comments (with indentation cleanup) below.
<html>
<head>
<title>Something Amazing Will Happen</title>
<style type="text/css">
body.light {
background-color: white;
}
body.dark {
background-color: black;
}
div.outside-wrapper {
position: absolute;
top: 50%;
width: 100%;
height: 1px;
overflow: visible;
}
div.inside-wrapper {
position: absolute;
top: 50%;
left: 50%;
width: 381px;
height: 393px;
margin: -197px 0 0 -191px;
cursor: pointer;
}
</style>
<script type="text/javascript">
styleIndex = 0;
var states = [{style: "light", image: "soon1a.png"}, {style: "dark", image: "soon2a.png"}];
function nextStyle() {
if (++styleIndex >= states.length)
styleIndex = 0;
var state = states[styleIndex];
document.body.className = state.style;
document.getElementById("clickme").src = state.image;
}
var tap = true;
document.addEventListener('touchstart',function(e) {
tap = true;
});
document.addEventListener('click',function(e) {
nextStyle()
tap = false;
});
document.addEventListener('touchmove',function(e) {
tap = false;
});
document.addEventListener('touchend',function(e) {
if(tap)
nextStyle();
});
</script>
</head>
<body class="light">
<div class="outside-wrapper">
<div class="inside-wrapper">
<img src="soon1a.png" id="clickme">
</div>
</div>
</body>
</html>
<!-- Don't ask me what it is. -->
Try this
body.soon1 {
background-color: white;
background-image: url(soon1a.png);
background-position: center;
background-repeat: no-repeat;
}
body.soon1:active{
cursor: pointer;
}
What you can do is, put the cursor: pointer on body and change the cursor on the childs. Do somthing like this: http://jsfiddle.net/HSdH3/
html:
<body>
<div></div>
</body>
css:
body {
background: red;
width:100%;
height: 100%;
}
body:hover {
cursor: pointer;
}
div {
width: 300px;
height: 300px;
margin: 0 auto;
background: white;
}
div:hover {
cursor: auto;
}
Something like this should work:
<div id="myDiv" style="cursor: pointer">
Another option is to use jQuery, although it may be overkill for this. Regardless, here's what it would look like:
$(document).ready(function(){
$("#myDiv").hover(function() {
$(this).css('cursor', 'pointer');
});
});
Check it out here: http://jsfiddle.net/K5fex/

Prevent body scrolling but allow overlay scrolling

I've been searching for a "lightbox" type solution that allows this but haven't found one yet (please, suggest if you know of any).
The behavior I'm trying to recreate is just like what you'd see at Pinterest when clicking on an image. The overlay is scrollable (as in the whole overlay moves up like a page on top of a page) but the body behind the overlay is fixed.
I attempted to create this with just CSS (i.e. a div overlay on top of the whole page and body with overflow: hidden), but it doesn't prevent div from being scrollable.
How to keep the body/page from scrolling but keep scrolling inside the fullscreen container?
Theory
Looking at current implementation of the pinterest site (it might change in the future), when you open the overlay, a noscroll class is applied to the body element (setting overflow: hidden) making the body no longer scrollable.
The overlay created on-the-fly or already injected in the page and made visible via display: block — it makes no difference – has position : fixed and overflow-y: scroll, with top, left, right and bottom properties set to 0: this style makes the overlay fill the whole viewport (but now we are in 2022, so you may use inset: 0 instead).
The div inside the overlay is in position: static so the vertical scrollbar is related to that element. This is resulting in a scrollable but fixed overlay.
When you close the overlay, you have to hide it (using display: none) and you could even remove the node via javascript (or just the content inside, it's up to you but also depends on the nature of the content).
The final step is to also remove the noscroll class applied to the body (so the overflow property gets back to the value it had previously)
Code
Codepen Example
(it works by changing the aria-hidden attribute of the overlay in order to show and hide it and to increase its accessibility).
Markup
(open button)
<button type="button" class="open-overlay">OPEN LAYER</button>
(overlay and close button)
<section class="overlay" aria-hidden="true" tabindex="-1">
<div>
<h2>Hello, I'm the overlayer</h2>
...
<button type="button" class="close-overlay">CLOSE LAYER</button>
</div>
</section>
CSS
.noscroll {
overflow: hidden;
}
.overlay {
position: fixed;
overflow-y: scroll;
inset: 0; }
[aria-hidden="true"] { display: none; }
[aria-hidden="false"] { display: block; }
Javascript (vanilla-JS)
var body = document.body,
overlay = document.querySelector('.overlay'),
overlayBtts = document.querySelectorAll('button[class$="overlay"]'),
openingBtt;
[].forEach.call(overlayBtts, function(btt) {
btt.addEventListener('click', function() {
/* Detect the button class name */
var overlayOpen = this.className === 'open-overlay';
/* storing a reference to the opening button */
if (overlayOpen) {
openingBtt = this;
}
/* Toggle the aria-hidden state on the overlay and the
no-scroll class on the body */
overlay.setAttribute('aria-hidden', !overlayOpen);
body.classList.toggle('noscroll', overlayOpen);
/* On some mobile browser when the overlay was previously
opened and scrolled, if you open it again it doesn't
reset its scrollTop property */
overlay.scrollTop = 0;
/* forcing focus for Assistive technologies but note:
- if your modal has just a phrase and a button move the
focus on the button
- if your modal has a long text inside (e.g. a privacy
policy) move the focus on the first heading inside
the modal
- otherwise just focus the modal.
When you close the overlay restore the focus on the
button that opened the modal.
*/
if (overlayOpen) {
overlay.focus();
}
else {
openingBtt.focus();
openingBtt = null;
}
}, false);
});
/* detect Escape key when the overlay is open */
document.body.addEventListener('keyup', (ev) => {
if (ev.key === "Escape" && overlay.getAttribute('aria-hidden') === 'false') {
overlay.setAttribute('aria-hidden', 'true');
body.classList.toggle('noscroll', false);
openingBtt.focus();
openingBtt = null;
}
})
Finally, here's another example in which the overlay opens with a fade-in effect by a CSS transition applied to the opacity property. Also a padding-right is applied to avoid a reflow on the underlying text when the scrollbar disappears.
Codepen Example (fade)
CSS
.noscroll { overflow: hidden; }
#media (min-device-width: 1025px) {
/* not strictly necessary, just an experiment for
this specific example and couldn't be necessary
at all on some browser */
.noscroll {
padding-right: 15px;
}
}
.overlay {
position: fixed;
overflow-y: scroll;
inset: 0;
}
[aria-hidden="true"] {
transition: opacity 1s, z-index 0s 1s;
width: 100vw;
z-index: -1;
opacity: 0;
}
[aria-hidden="false"] {
transition: opacity 1s;
width: 100%;
z-index: 1;
opacity: 1;
}
overscroll-behavior css property allows to override the browser's default overflow scroll behavior when reaching the top/bottom of content.
Just add the following styles to overlay:
.overlay {
overscroll-behavior: contain;
...
}
Codepen demo
Currently works in Chrome, Firefox and IE(caniuse)
For more details check google developers article.
If you want to prevent overscrolling on ios, you can add position fixed to your .noscroll class
body.noscroll{
position:fixed;
overflow:hidden;
}
Most solutions have the problem that they do not retain the scroll position, so I took a look at how Facebook does it. In addition to setting the underlaying content to position: fixed they also set the top dynamically to retain the scroll position:
scrollPosition = window.pageYOffset;
mainEl.style.top = -scrollPosition + 'px';
Then, when you remove the overlay again, you need to reset the scroll position:
window.scrollTo(0, scrollPosition);
I created a little example to demonstrate this solution
let overlayShown = false;
let scrollPosition = 0;
document.querySelector('.toggle').addEventListener('click', function() {
if (!overlayShown) {
showOverlay();
} else {
removeOverlay();
}
overlayShown = !overlayShown;
});
function showOverlay() {
scrollPosition = window.pageYOffset;
const mainEl = document.querySelector('.main-content');
mainEl.style.top = -scrollPosition + 'px';
document.body.classList.add('show-overlay');
}
function removeOverlay() {
document.body.classList.remove('show-overlay');
window.scrollTo(0, scrollPosition);
const mainEl = document.querySelector('.main-content');
mainEl.style.top = 0;
}
.main-content {
background-image: repeating-linear-gradient( lime, blue 103px);
width: 100%;
height: 200vh;
}
.show-overlay .main-content {
position: fixed;
left: 0;
right: 0;
overflow-y: scroll; /* render disabled scroll bar to keep the same width */
/* Suggestion to put: overflow-y: hidden;
Disabled scrolling still makes a mess with its width. Hiding it does the trick. */
}
.overlay {
display: none;
position: fixed;
top: 0;
left: 0;
width: 100%;
height: 100%;
background: rgba(0, 0, 0, 0.3);
overflow: auto;
}
.show-overlay .overlay {
display: block;
}
.overlay-content {
margin: 50px;
background-image: repeating-linear-gradient( grey, grey 20px, black 20px, black 40px);
height: 120vh;
}
.toggle {
position: fixed;
top: 5px;
left: 15px;
padding: 10px;
background: red;
}
/* reset CSS */
body {
margin: 0;
}
<main class="main-content"></main>
<div class="overlay">
<div class="overlay-content"></div>
</div>
<button class="toggle">Overlay</button>
Don't use overflow: hidden; on body. It automatically scrolls everything to the top. There's no need for JavaScript either. Make use of overflow: auto;. This solution even works with mobile Safari:
HTML Structure
<div class="overlay">
<div class="overlay-content"></div>
</div>
<div class="background-content">
lengthy content here
</div>
Styling
.overlay{
position: fixed;
top: 0px;
left: 0px;
right: 0px;
bottom: 0px;
background-color: rgba(0, 0, 0, 0.8);
.overlay-content {
height: 100%;
overflow: scroll;
}
}
.background-content{
height: 100%;
overflow: auto;
}
See the demo here and source code here.
Update:
For people who want keyboard space bar, page up/down to work: you need to focus on the overlay, e.g., clicking on it, or manually JS focusing on it before this part of the div will respond to keyboard. Same with when the overlay is "switched off", since it's just moving the overlay to the side. Otherwise to browser, these are just two normal divs and it wouldn't know why it should focus on any one of them.
It is worth noting that sometimes adding "overflow:hidden" to the body tag doesn't do the job. In those cases, you'll have to add the property to the html tag as well.
html, body {
overflow: hidden;
}
The behaviour you want to prevent is called scroll chaining. To disable it, set
overscroll-behavior: contain;
on your overlay in CSS.
You can easily do this with some "new" css and JQuery.
Initially: body {... overflow:auto;}
With JQuery you can dynamically switch between 'overlay' and 'body'. When on 'body', use
body {
position: static;
overflow: auto;
}
When on 'overlay' use
body {
position: sticky;
overflow: hidden;
}
JQuery for the switch('body'->'overlay'):
$("body").css({"position": "sticky", "overflow": "hidden"});
JQuery for the switch('overlay'->'body'):
$("body").css({"position": "static", "overflow": "auto"});
if anyone is looking for a solution for React function components, you can put this inside the modal component:
useEffect(() => {
document.body.style.overflowY = 'hidden';
return () =>{
document.body.style.overflowY = 'auto';
}
}, [])
Generally speaking, if you want a parent (the body in this case) to prevent it from scrolling when a child (the overlay in this case) scrolls, then make the child a sibling of the parent to prevent the scroll event from bubbling up to the parent. In case of the parent being the body, this requires an additional wrapping element:
<div id="content">
</div>
<div id="overlay">
</div>
See Scroll particular DIV contents with browser's main scrollbar to see its working.
The chosen answer is correct, but has some limitations:
Super hard "flings" with your finger will still scroll <body> in the background
Opening the virtual keyboard by tapping an <input> in the modal will direct all future scrolls to <body>
I don't have a fix for the first issue, but wanted to shed some light on the second. Confusingly, Bootstrap used to have the keyboard issue documented, but they claimed it was fixed, citing http://output.jsbin.com/cacido/quiet as an example of the fix.
Indeed, that example works fine on iOS with my tests. However, upgrading it to the latest Bootstrap (v4) breaks it.
In an attempt to figure out what the difference between them was, I reduced a test case to no longer depend on Bootstrap, http://codepen.io/WestonThayer/pen/bgZxBG.
The deciding factors are bizarre. Avoiding the keyboard issue seems to require that background-color is not set on the root <div> containing the modal and the modal's content must be nested in another <div>, which can have background-color set.
To test it, uncomment the below line in the Codepen example:
.modal {
position: fixed;
top: 0;
right: 0;
bottom: 0;
left: 0;
z-index: 2;
display: none;
overflow: hidden;
-webkit-overflow-scrolling: touch;
/* UNCOMMENT TO BREAK */
/* background-color: white; */
}
For touch devices, try adding a 1px wide, 101vh min-height transparent div in the wrapper of the overlay. Then add -webkit-overflow-scrolling:touch; overflow-y: auto; to the wrapper. This tricks mobile safari into thinking the overlay is scrollable, thus intercepting the touch event from the body.
Here's a sample page. Open on mobile safari: http://www.originalfunction.com/overlay.html
https://gist.github.com/YarGnawh/90e0647f21b5fa78d2f678909673507f
I found this question trying to solve issue I had with my page on Ipad and Iphone - body was scrolling when I was displaying fixed div as popup with image.
Some answers are good, however none of them solved my issue. I found following blog post by Christoffer Pettersson. Solution presented there helped issue I had with iOS devices and it helped my scrolling background problem.
Six things I learnt about iOS Safari's rubber band scrolling
As it was suggested I include major points of the blog post in case link gets outdated.
"In order to disable that the user can scroll the background page while the "menu is open", it is possible to control what elements should be allowed to be scrolled or not, by applying some JavaScript and a CSS class.
Based on this Stackoverflow answer you can control that elements with the disable-scrolling should not
perform their default scroll action when the touchmove event is triggered."
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();
}
};
And then put the disable-scrolling class on the page div:
<div class="page disable-scrolling">
Simple inline styling for the body tag:
<body style="position: sticky; overflow: hidden;">
If the intent is to disable on mobile/ touch devices then the most straightforward way to do it is using touch-action: none;.
Example:
const app = document.getElementById('app');
const overlay = document.getElementById('overlay');
let body = '';
for (let index = 0; index < 500; index++) {
body += index + '<br />';
}
app.innerHTML = body;
app.scrollTop = 200;
overlay.innerHTML = body;
* {
margin: 0;
padding: 0;
}
html,
body {
height: 100%;
}
#app {
background: #f00;
position: absolute;
height: 100%;
width: 100%;
overflow-y: scroll;
line-height: 20px;
}
#overlay {
background: rgba(0,0,0,.5);
position: fixed;
top: 0;
left: 0;
right: 0;
height: 100%;
padding: 0 0 0 100px;
overflow: scroll;
}
<div id='app'></div>
<div id='overlay'></div>
(The example does not work in the context of Stack Overflow. You will need to recreate it in a stand-alone page.)
If you want to disable scrolling of the #app container, just add touch-action: none;.
I'd like to add to previous answers because I tried to do that, and some layout broke as soon as I switched the body to position:fixed. In order to avoid that, I had to also set body's height to 100% :
function onMouseOverOverlay(over){
document.getElementsByTagName("body")[0].style.overflowY = (over?"hidden":"scroll");
document.getElementsByTagName("html")[0].style.position = (over?"fixed":"static");
document.getElementsByTagName("html")[0].style.height = (over?"100%":"auto");
}
Use the following HTML:
<body>
<div class="page">Page content here</div>
<div class="overlay"></div>
</body>
Then JavaScript to intercept and stop scrolling:
$(".page").on("touchmove", function(event) {
event.preventDefault()
});
Then to get things back to normal:
$(".page").off("touchmove");
In my case, none of these solutions worked out on iPhone (iOS 11.0).
The only effective fix that is working on all my devices is this one - ios-10-safari-prevent-scrolling-behind-a-fixed-overlay-and-maintain-scroll-position
try this
var mywindow = $('body'), navbarCollap = $('.navbar-collapse');
navbarCollap.on('show.bs.collapse', function(x) {
mywindow.css({visibility: 'hidden'});
$('body').attr("scroll","no").attr("style", "overflow: hidden");
});
navbarCollap.on('hide.bs.collapse', function(x) {
mywindow.css({visibility: 'visible'});
$('body').attr("scroll","yes").attr("style", "");
});
One solution for a React functional component is to use the useEffect hook.
Here's the code example bellow (pay attention to the useEffect definition):
import {useEffect, useRef} from "react";
export default function PopoverMenu({className, handleClose, children}) {
const selfRef = useRef(undefined);
useEffect(() => {
const isPopoverOpenned = selfRef.current?.style.display !== "none";
const focusedElement = document?.activeElement;
const scrollPosition = {x: window.scrollX, y: window.scrollY};
if (isPopoverOpenned) {
preventDocBodyScrolling();
} else {
restoreDocBodyScrolling();
}
function preventDocBodyScrolling() {
const width = document.body.clientWidth;
const hasVerticalScrollBar = (window.innerWidth > document.documentElement.clientWidth);
document.body.style.overflowX = "hidden";
document.body.style.overflowY = hasVerticalScrollBar ? "scroll" : "";
document.body.style.width = `${width}px`;
document.body.style.position = "fixed";
}
function restoreDocBodyScrolling() {
document.body.style.overflowX = "";
document.body.style.overflowY = "";
document.body.style.width = "";
document.body.style.position = "";
focusedElement?.focus();
window.scrollTo(scrollPosition.x, scrollPosition.y);
}
return () => {
restoreDocBodyScrolling(); // cleanup on unmount
};
}, []);
return (
<>
<div
className="backdrop"
onClick={() => handleClose && handleClose()}
/>
<div
className={`pop-over-menu${className ? (` ${className}`) : ""}`}
ref={selfRef}
>
<button
className="pop-over-menu--close-button" type="button"
onClick={() => handleClose && handleClose()}
>
X
</button>
{children}
</div>
</>
);
}
Originally posted on this other related Stackoverflow question: https://stackoverflow.com/a/69016517/14131330
CSS
.noScroll {
overflow: hidden;
}
Javascript
<script>
function toggleNav() {
document.body.classList.toggle("noScroll");
}
</script>
Button
<button onclick="toggleNav()">
Toggle Nav
</button>
If you want to stop body/html scroll add as the following
CSS
html, body {
height: 100%;
}
.overlay{
position: fixed;
top: 0px;
left: 0px;
right: 0px;
bottom: 0px;
background-color: rgba(0, 0, 0, 0.8);
.overlay-content {
height: 100%;
overflow: scroll;
}
}
.background-content{
height: 100%;
overflow: auto;
}
HTML
<div class="overlay">
<div class="overlay-content"></div>
</div>
<div class="background-content">
lengthy content here
</div>
Basically, you could do it without JS.
The main idea is to add html/body with height: 100% and overflow: auto.
and inside your overlay, you could either enable/disable scroll based on your requirement.
Hope this helps!
Use below code for disabling and enabling scroll bar.
Scroll = (
function(){
var x,y;
function hndlr(){
window.scrollTo(x,y);
//return;
}
return {
disable : function(x1,y1){
x = x1;
y = y1;
if(window.addEventListener){
window.addEventListener("scroll",hndlr);
}
else{
window.attachEvent("onscroll", hndlr);
}
},
enable: function(){
if(window.removeEventListener){
window.removeEventListener("scroll",hndlr);
}
else{
window.detachEvent("onscroll", hndlr);
}
}
}
})();
//for disabled scroll bar.
Scroll.disable(0,document.body.scrollTop);
//for enabled scroll bar.
Scroll.enable();

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