Question: Intersection Observer - Animation - javascript

I spent the weekend trying to get my head around the Intersection Observer Animation for an animation that I'm trying to achieve. From my understanding of the intersection observer my code should work as I intended but the reality is it doesn't 🥲
My goal is that the scroll animation starts when the element reaches a certain point within the viewport. In my codepen, I've marked the point where the animation should start with a border. However, the animation starts as soon as the div enters the viewport.
Also, when the element gets below the border again, the animation should stop.
I would very much appreciate any help to achieve my goal.
Code example: https://codepen.io/aki-sol/pen/RwJPJrW?editors=1111
Also, if you have any feedback on my animation approach I'm very happy to receive criticism/ better way of approaching this.
<div class="text">
Lorem ipsum, dolor sit amet consectetur adipisicing elit. Expedita provident unde, sequi aliquid porro ipsa vitae nulla dolor neque aliquam quisquam nam magnam architecto, consequuntur est in beatae, nihil optio.
Lorem ipsum dolor sit amet, consectetur adipisicing elit. Et, architecto eveniet assumenda praesentium in laboriosam vitae atque, sunt minima aliquid quam distinctio voluptatum commodi veniam iure officia provident voluptas ea?
Lorem ipsum dolor sit amet consectetur adipisicing elit. Eveniet quo commodi laborum perspiciatis nemo voluptates quod odio quis necessitatibus perferendis? Ipsum, quasi nesciunt. Debitis omnis consequuntur laboriosam veniam, non impedit!
</div>
<div class="box">
<div class="box-content"></div>
<div class="box-content"></div>
<div class="box-content"></div>
<div class="box-content"></div>
<div class="box-content"></div>
<div class="box-content"></div>
<div class="box-content"></div>
<div class="box-content"></div>
<div class="box-content"></div>
<div class="box-content"></div>
<div class="box-content"></div>
<div class="box-content"></div>
</div>
<div class="text">
Lorem ipsum, dolor sit amet consectetur adipisicing elit. Expedita provident unde, sequi aliquid porro ipsa vitae nulla dolor neque aliquam quisquam nam magnam architecto, consequuntur est in beatae, nihil optio.
Lorem ipsum dolor sit amet, consectetur adipisicing elit. Et, architecto eveniet assumenda praesentium in laboriosam vitae atque, sunt minima aliquid quam distinctio voluptatum commodi veniam iure officia provident voluptas ea?
Lorem ipsum dolor sit amet consectetur adipisicing elit. Eveniet quo commodi laborum perspiciatis nemo voluptates quod odio quis necessitatibus perferendis? Ipsum, quasi nesciunt. Debitis omnis consequuntur laboriosam veniam, non impedit!
</div>
body {
position: relatvie;
heig;
}
body:after {
content: '';
position: fixed;
bottom: 40%;
height: 1px;
width: 100%;
border-bottom: 1px solid blue;
}
.text {
background-color: brown;
color: white;
height: 150vh;
}
.box {
display: flex;
position: relative;
}
.box-content {
width: 200px;
height: 200px;
background-color: greenyellow;
margin-right: 50px;
}
const boxElement = document.querySelector(".box");
//this function calls the aniamtion function and observes the window scroll position
function getWindowScrollPos() {
let windowPosition = window.scrollY;
window.addEventListener("scroll", () => {
windowPosition = window.scrollY;
animateBox(boxElement, windowPosition);
});
}
function animateBox(box, scrollPosition) {
let boxOffsetPosition = scrollPosition;
box.style.left = `${-boxOffsetPosition}px `;
}
function boxObserver(element) {
const observer = new IntersectionObserver(
(entries, observer) => {
entries.forEach((entry) => {
if (entry.isIntersecting) {
getWindowScrollPos();
}
});
},
{ rootMargin: "0% 0% 60% 0%" }
);
observer.observe(element);
}
boxObserver(boxElement);
Thanks a lot!


There are two things to note here, I guess.
First, the Intersection Observer (along with Resize Observer) is not the best thing to test in online sandboxes, because they run code in an iframe, which leads to such a behavior. You should try to run your code in a browser.
There are questions related to this problem. E.g.: In codepen, Intersection observer has different behavior from browser window
Second, you're probably misunderstanding rootMargin. You set it to 0% 0% 60% 0% which means “add 60% of the height of the root to the very root, and use it as a bottom border for intersection”.
What you actually want to is to decrease the bottom border, not to increase. So, just set it to 0% 0% -40% 0% and it will work.
The Intersection Observer tutorial that helped me a bit to understand the rootMargin weirdness. Maybe it will be useful for you too.
Demo
Here's your snippet that I changed a bit to make it work inside an iframe. I've added a container node and use it instead of window.
const boxElement = document.querySelector('.box');
const container = document.getElementById('container');
function setupListener() {
let scrollPosition = container.scrollTop;
animateBox(boxElement, scrollPosition);
container.addEventListener('scroll', () => {
scrollPosition = container.scrollTop;
animateBox(boxElement, scrollPosition);
});
}
function animateBox(box, scrollPosition) {
let boxOffsetPosition = scrollPosition;
box.style.left = `${-boxOffsetPosition}px`;
}
function boxObserver(element) {
const observer = new IntersectionObserver(
(entries, observer) => {
entries.forEach((entry) => {
if (entry.isIntersecting) {
setupListener();
}
});
},
{
root: document.getElementById('container'),
rootMargin: `0px 0px -40% 0px`
}
);
observer.observe(element);
}
boxObserver(boxElement);
body {
margin: 0;
overflow: hidden;
}
body:after {
content: "";
position: fixed;
bottom: 40%;
height: 1px;
width: 100%;
border-bottom: 1px solid blue;
}
.container {
overflow: scroll;
max-height: 100vh;
}
.text {
background-color: brown;
color: white;
height: 150vh;
}
.box {
display: flex;
position: relative;
}
.box-content {
width: 200px;
height: 200px;
background-color: greenyellow;
margin-right: 50px;
}
<div class="container" id="container">
<div class="text">
Lorem ipsum, dolor sit amet consectetur adipisicing elit. Expedita provident unde, sequi aliquid porro ipsa vitae nulla dolor neque aliquam quisquam nam magnam architecto, consequuntur est in beatae, nihil optio.
Lorem ipsum dolor sit amet, consectetur adipisicing elit. Et, architecto eveniet assumenda praesentium in laboriosam vitae atque, sunt minima aliquid quam distinctio voluptatum commodi veniam iure officia provident voluptas ea?
Lorem ipsum dolor sit amet consectetur adipisicing elit. Eveniet quo commodi laborum perspiciatis nemo voluptates quod odio quis necessitatibus perferendis? Ipsum, quasi nesciunt. Debitis omnis consequuntur laboriosam veniam, non impedit!
</div>
<div class="box">
<div class="box-content"></div>
<div class="box-content"></div>
<div class="box-content"></div>
<div class="box-content"></div>
<div class="box-content"></div>
<div class="box-content"></div>
<div class="box-content"></div>
<div class="box-content"></div>
<div class="box-content"></div>
<div class="box-content"></div>
<div class="box-content"></div>
<div class="box-content"></div>
</div>
<div class="text">
Lorem ipsum, dolor sit amet consectetur adipisicing elit. Expedita provident unde, sequi aliquid porro ipsa vitae nulla dolor neque aliquam quisquam nam magnam architecto, consequuntur est in beatae, nihil optio.
Lorem ipsum dolor sit amet, consectetur adipisicing elit. Et, architecto eveniet assumenda praesentium in laboriosam vitae atque, sunt minima aliquid quam distinctio voluptatum commodi veniam iure officia provident voluptas ea?
Lorem ipsum dolor sit amet consectetur adipisicing elit. Eveniet quo commodi laborum perspiciatis nemo voluptates quod odio quis necessitatibus perferendis? Ipsum, quasi nesciunt. Debitis omnis consequuntur laboriosam veniam, non impedit!
</div>
</div>
What may be improved
Also, if you have any feedback on my animation approach I'm very happy to receive criticism/ better way of approaching this.
Well, you surely should think about the scroll listener you will have after the intersection started. If you don't remove it, it will hang. Or even worse, they will be increasing during each intersection. Not a good thing.
Also it's better to animate transform, not left. It's good for optimization. Otherwise you'll get junky animation which will freeze the whole site. Check this set of articles by Google: web.dev/animations/.

Related

How to slid left/right two divs using jquery?

I am new to coding and I am trying to achieve the following using JQuery:
I have two Divs Where clicking on the first shows some content and clicking the second would hide the content of the first one and show its content instead (Toggling). What I want to do is that I want to keep the same functionality but I want the second Div to slide to the right when I click on the first Div and make a drawer shape and vice versa. I have attached images to it so it may explain more about my idea.
both of contents are hidden by default.
I can't seem to know how to join these two functionalities together
HTML
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Test</title>
<script
src="https://code.jquery.com/jquery-3.5.1.js"
integrity="sha256-QWo7LDvxbWT2tbbQ97B53yJnYU3WhH/C8ycbRAkjPDc="
crossorigin="anonymous"
></script>
<link rel="stylesheet" href="style.css" />
<script src="script.js"></script>
</head>
<body>
<div id="box-container">
<div id="div1">
<h1>Title one</h1>
<p>
Lorem ipsum dolor sit amet consectetur, adipisicing elit. Inventore
quidem ex tenetur ipsum dolore repudiandae molestiae mollitia! Dolore
numquam.
</p>
</div>
<div id="div2">
<h1>Title two</h1>
<p>
Lorem ipsum dolor sit amet consectetur, adipisicing elit. Inventore
quidem ex tenetur ipsum dolore repudiandae molestiae mollitia! Dolore
numquam.
</p>
</div>
</div>
<div id="contentDiv1">
Lorem ipsum dolor sit amet consectetur adipisicing elit. Nulla voluptatem
veritatis assumenda. Obcaecati veniam quo impedit tempora pariatur maiores
ipsa voluptates commodi esse eveniet! Nihil corrupti illum at accusantium
sit? Lorem ipsum dolor sit amet consectetur adipisicing elit. Ut veritatis
et molestias? Reprehenderit distinctio sint provident ratione dolorem
veritatis sapiente, fuga amet obcaecati. Laboriosam rerum consectetur nemo
magnam saepe mollitia. Lorem ipsum dolor sit amet consectetur adipisicing
elit. Excepturi sit perferendis earum debitis corrupti dolore commodi
minima consectetur veniam itaque inventore et pariatur sapiente, maxime
quis, in nulla, eos molestias! Lorem ipsum dolor sit amet consectetur,
adipisicing elit. Quasi, incidunt repudiandae perferendis ea praesentium
blanditiis, voluptate accusantium, repellat molestiae quisquam eveniet
earum officia sed assumenda maxime officiis sequi laboriosam! Tempore.
Lorem ipsum dolor sit amet consectetur adipisicing elit. Alias modi hic
officia iste optio in delectus veniam obcaecati reprehenderit, voluptate
ipsum! Incidunt ducimus animi, id quae blanditiis provident dignissimos
harum?
</div>
<div id="contentDiv2">
Lorem ipsum dolor sit amet consectetur adipisicing elit. Nulla voluptatem
veritatis assumenda. Obcaecati veniam quo impedit tempora pariatur maiores
ipsa voluptates commodi esse eveniet! Nihil corrupti illum at accusantium
sit? Lorem ipsum dolor sit amet consectetur adipisicing elit. Ut veritatis
et molestias? Reprehenderit distinctio sint provident ratione dolorem
veritatis sapiente, fuga amet obcaecati. Laboriosam rerum consectetur nemo
magnam saepe mollitia. Lorem ipsum dolor sit amet consectetur adipisicing
elit. Excepturi sit perferendis earum debitis corrupti dolore commodi
minima consectetur veniam itaque inventore et pariatur sapiente, maxime
quis, in nulla, eos molestias! Lorem ipsum dolor sit amet consectetur,
adipisicing elit. Quasi, incidunt repudiandae perferendis ea praesentium
blanditiis, voluptate accusantium, repellat molestiae quisquam eveniet
earum officia sed assumenda maxime officiis sequi laboriosam! Tempore.
Lorem ipsum dolor sit amet consectetur adipisicing elit. Alias modi hic
officia iste optio in delectus veniam obcaecati reprehenderit, voluptate
ipsum! Incidunt ducimus animi, id quae blanditiis provident dignissimos
harum?
</div>
</body>
</html>
CSS
body {
display: inline-block;
margin: 100px 100px 25px 100px;
text-align: center;
}
#box-container {
height: 300px;
display: flex;
}
#div1 {
background: linear-gradient(90deg, #f57350, #fa8282);
width: 50%;
height: 50%;
cursor: pointer;
}
#div2 {
background: linear-gradient(90deg, #a42e5a, #f57350);
width: 50%;
height: 50%;
cursor: pointer;
}
#contentDiv1,
#contetnDiv2 {
margin: 25px;
}
JQuery
jQuery(document).ready(function($){
$('#contentDiv1').hide();
$('#contentDiv2').hide();
$('#div1').on('click', function(){
$('#contentDiv1').slideToggle();
$('#contentDiv2').hide();
});
$('#div2').on('click', function(){
$('#contentDiv2').slideToggle();
$('#contentDiv1').hide();
});
});
attached image

It has more than one solution, and for me, this is my favorite method, I hope it helps you:
$('.tabs .tab').on('click', function () {
if ($(this).hasClass('active')) {
$(this).removeClass('active')
.closest('.tabs').removeClass('active1 active2');
$('.content').hide();
} else {
let i = $(this).index() + 1;
$(this)
.addClass('active')
.siblings('.tab').removeClass('active')
.closest('.tabs').removeClass('active1 active2')
.addClass('active' + i);
$('.content').hide();
$('.content' + i).fadeIn();
}
});
.tabs,
.tabs .tab,
.tabs .content {
border: 1px solid #000;
border-collapse: collapse;
box-sizing: border-box;
}
.tabs {
display: flex;
flex-wrap: wrap;
text-align: center;
position: relative;
}
.tabs.active1 {
padding-left: 0;
padding-right: 65px;
}
.tabs.active2 {
padding-left: 65px;
padding-right: 0;
}
.tabs .tab {
padding: 15px;
cursor: pointer;
min-width: 50%;
display: flex;
justify-content: center;
align-items: center;
}
.tabs.active1 .tab,
.tabs.active2 .tab {
min-width: 100%;
width: 100%;
}
.tabs .content {
padding: 15px;
min-width: 100%;
display: none;
}
.tabs.active1 .tab1:not(.active),
.tabs.active2 .tab1:not(.active){
position: absolute;
left: 0;
top: 0;
bottom: 0;
min-width: 65px;
width: 65px;
}
.tabs.active1 .tab2:not(.active),
.tabs.active2 .tab2:not(.active) {
position: absolute;
right: 0;
top: 0;
bottom: 0;
min-width: 65px;
width: 65px;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="tabs">
<div class="tab tab1">div1</div>
<div class="tab tab2">div2</div>
<div class="content content1">div content1</div>
<div class="content content2">div content2</div>
</div>

CSS Scroll-snap with children nested in overflow: hidden element

Is it possible to apply scroll-snap to grand-children nested in children with overflow applied ? I can't seem to make it work.
What I aim to do is have a list of div with each a fixed height on which the viewport should snap vertically
html {
margin: 0;
scroll-snap-type: y mandatory;
overflow-x: hidden;
}
.horizontal-scroll {
max-width: 100vw;
}
.child {
width: 150vw;
scroll-snap-align: center;
height: 80vh;
background-color: rgb(143, 204, 241);
padding: 20px 15px;
}
.child:nth-child(even) {
background-color: rgb(133, 243, 155);
}
<!DOCTYPE html>
<html>
<head
</head>
<body>
<div class="horizontal-scroll">
<div class="child">
<h2>Section</h2>
<p>
Lorem ipsum dolor sit amet consectetur adipisicing elit. Vel laboriosam cupiditate vero, harum, ab facere ipsa mollitia exercitationem impedit alias nulla magnam aut tempore repudiandae
dolores. Sit maiores nemo ea.
</p>
</div> <div class="child">
<h2>Section</h2>
<p>
Lorem ipsum dolor sit amet consectetur adipisicing elit. Vel laboriosam cupiditate vero, harum, ab facere ipsa mollitia exercitationem impedit alias nulla magnam aut tempore repudiandae
dolores. Sit maiores nemo ea.
</p>
</div>
<div class="child">
<h2>Section</h2>
<p>
Lorem ipsum dolor sit amet consectetur adipisicing elit. Vel laboriosam cupiditate vero, harum, ab facere ipsa mollitia exercitationem impedit alias nulla magnam aut tempore repudiandae
dolores. Sit maiores nemo ea.
</p>
</div>
</div>
</body>
</html>
Homewer, I would also like the content to be horizontally-scrollable - as their content stretch beyond the viewport width.
They must also scroll together, so using overflow-x on each of them is not possible here.
To do so, I've wrapped the child in a scrollable-wrapper that is horizontally scrollable ( overflow-x : scroll ) and have a fixed width.
And this breaks the vertical scroll snap.
Could someone tell me if there's something I missed or if there's an alternative ?
Note : since each child have a fixed height, I would not mind using scroll-snap-points-y but it has been totally dropped on almost every browser. Is there a way to reproduce this behaviour ?
Edit : I might try this for the snap-point. It's jQuery based.
Vertical scrolling snap jQuery
Snippet
html {
margin: 0;
scroll-snap-type: y mandatory;
overflow-x: hidden;
}
.horizontal-scroll {
max-width: 100vw;
overflow-x: scroll;
}
.child {
width: 150vw;
scroll-snap-align: center;
height: 80vh;
background-color: rgb(143, 204, 241);
padding: 20px 15px;
}
.child:nth-child(even) {
background-color: rgb(133, 243, 155);
}
<!DOCTYPE html>
<html>
<head>
</head>
<body>
<div class="horizontal-scroll">
<div class="child">
<h2>Section</h2>
<p>
Lorem ipsum dolor sit amet consectetur adipisicing elit. Vel laboriosam cupiditate vero, harum, ab facere ipsa mollitia exercitationem impedit alias nulla magnam aut tempore repudiandae
dolores. Sit maiores nemo ea.
</p>
</div> <div class="child">
<h2>Section</h2>
<p>
Lorem ipsum dolor sit amet consectetur adipisicing elit. Vel laboriosam cupiditate vero, harum, ab facere ipsa mollitia exercitationem impedit alias nulla magnam aut tempore repudiandae
dolores. Sit maiores nemo ea.
</p>
</div>
<div class="child">
<h2>Section</h2>
<p>
Lorem ipsum dolor sit amet consectetur adipisicing elit. Vel laboriosam cupiditate vero, harum, ab facere ipsa mollitia exercitationem impedit alias nulla magnam aut tempore repudiandae
dolores. Sit maiores nemo ea.
</p>
</div>
</div>
</body>
</html>

Displaying the image in the background when scrolling text

I create an effect that is to constantly display the image while scrolling text. I have a question how to make it work the same way, instead of position: sticky, posititon: fixed, so that this effect works on ie.
var sticky = document.querySelector('.sticky-container');
var img = document.querySelector('.sticky-item');
window.addEventListener('scroll',setSticky);
function setSticky(){
var top = sticky.offsetTop - window.pageYOffset;
if(top <= 0){
sticky.classList.add('sticky');
}
if(top.toString().replace('-','') >= sticky.offsetHeight || top >= 0){
sticky.classList.remove('sticky');
}
};
* {
margin: 0;
}
body {
width: 100%;
padding: 120vh 0;
}
p {
font-size: 28px;
color: #fff;
text-align: center;
margin: 80px 0;
}
.sticky-item {
width: 100%;
height: 100vh;
background: url(https://www.apple.com/v/iphone-xs/a/images/overview/camera_hero_large.jpg) center / cover no-repeat;
}
.sticky-container.sticky .sticky-item{
position: sticky;
top: 0;
z-index: -1;
}
<div class="sticky-container">
<figure class="sticky-item"></figure>
<p class="anim">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Sint, magni suscipit modi enim assumenda optio tenetur recusandae sed nobis veritatis!</p>
<p class="anim">Lorem ipsum dolor sit amet consectetur adipisicing elit. A, at.</p>
<p class="anim">Lorem ipsum dolor sit amet consectetur adipisicing elit. Velit laudantium, esse omnis neque, minima voluptatibus repellendus amet, quod odio architecto veniam fuga inventore adipisci! Delectus fugit quisquam ad, ab facilis at saepe? Soluta delectus consequuntur fuga ipsa quasi dolorem officiis?</p>
<p>Lorem, ipsum dolor sit amet consectetur adipisicing elit. Cumque dolorum ipsum distinctio ut excepturi facilis laborum, nihil in aliquid assumenda necessitatibus quaerat recusandae. Nobis, dolore? Hic itaque ipsa inventore illo tempora similique perspiciatis architecto rem, nulla dicta error saepe earum ut atque aut aspernatur deserunt doloribus odit ea, a reprehenderit?</p>
</div>

EDIT:
<div class="sticky-container">
<p class="anim">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Sint, magni suscipit modi enim assumenda optio tenetur recusandae sed nobis veritatis!</p>
<p class="anim">Lorem ipsum dolor sit amet consectetur adipisicing elit. A, at.</p>
<p class="anim">Lorem ipsum dolor sit amet consectetur adipisicing elit. Velit laudantium, esse omnis neque, minima voluptatibus repellendus amet, quod odio architecto veniam fuga inventore adipisci! Delectus fugit quisquam ad, ab facilis at saepe? Soluta delectus consequuntur fuga ipsa quasi dolorem officiis?</p>
<p>Lorem, ipsum dolor sit amet consectetur adipisicing elit. Cumque dolorum ipsum distinctio ut excepturi facilis laborum, nihil in aliquid assumenda necessitatibus quaerat recusandae. Nobis, dolore? Hic itaque ipsa inventore illo tempora similique perspiciatis architecto rem, nulla dicta error saepe earum ut atque aut aspernatur deserunt doloribus odit ea, a reprehenderit?</p>
</div>
.sticky-item {
background-attachment: fixed;
background-size: 100%;
}
Dai is correct, you do not need to use a script to achieve this effect.
https://jsfiddle.net/tractionworks/h3r5uvqm/8/

Since you need to use the position:sticky feature I doubt this works on IE without a big effort and actually using JS. But with 1.4% global usage I doubt this is worth your time.
However if you are fine with the coverage of sticky, I would entirely skip using JS and solve it via CSS:
* {
margin: 0;
}
body {
width: 100%;
padding: 120vh 0;
}
p {
font-size: 28px;
color: #fff;
text-align: center;
margin: 80px 0;
}
.sticky-item {
position: sticky;
top: 0;
z-index: -1;
width: 100%;
height: 100vh;
background: url(https://www.apple.com/v/iphone-xs/a/images/overview/camera_hero_large.jpg) center / cover no-repeat;
}
<div class="sticky-item"></div>
<div class="sticky-container">
<p class="anim">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Sint, magni suscipit modi enim assumenda optio tenetur recusandae sed nobis veritatis!</p>
<p class="anim">Lorem ipsum dolor sit amet consectetur adipisicing elit. A, at.</p>
<p class="anim">Lorem ipsum dolor sit amet consectetur adipisicing elit. Velit laudantium, esse omnis neque, minima voluptatibus repellendus amet, quod odio architecto veniam fuga inventore adipisci! Delectus fugit quisquam ad, ab facilis at saepe? Soluta delectus consequuntur fuga ipsa quasi dolorem officiis?</p>
<p>Lorem, ipsum dolor sit amet consectetur adipisicing elit. Cumque dolorum ipsum distinctio ut excepturi facilis laborum, nihil in aliquid assumenda necessitatibus quaerat recusandae. Nobis, dolore? Hic itaque ipsa inventore illo tempora similique perspiciatis architecto rem, nulla dicta error saepe earum ut atque aut aspernatur deserunt doloribus odit ea, a reprehenderit?</p>
</div>

How to hide single div at a time without flashing rather setting visibility hidden

i want to hide a single div at a time so that below flashing can be avoided(shown in image)
NOTE: i cannot use visibility:hidden or visibility:show or $sel.css('visibility','hidden'); or $sel.css('visibility','show');
My Expectation: when I do $content.hide(); in the DOM see html area in image provided by me where style="display:none"/style="display:block" is happening for every element, rather I want to hide that particular element at a time (so no multiple display/hide at a time, only one display/hide) similar to #snippet2, #snippet1 should work (but hidden element should not contain any width/height)
below is my code which should work with display:none or $el.hide()/$el.show():
#Snippet1
$(function() {
var pos = 1;
var ii = 0;
var centerbandTop = $('.center-band').offset().top;
var centerbandBottom = $('.center-band').outerHeight() + centerbandTop;
$('.contents').hide();
var intId = setInterval(function() {
ii++;
pos = -ii;
//console.log(pos);
//if (pos )
$('.contents').each(function() {
var $content = $(this);
var contentTop = $content.offset().top;
var contentBottom = $content.outerHeight() + contentTop;
$content.hide();
//console.log($content.position().top, centerbandTop, contentBottom);
if (centerbandBottom > contentTop && centerbandTop < contentBottom)
$content.show();
});
$('.container').css({
// '-webkit-transform' : 'translate(0,' + pos + ')',
transform: 'translateY(' + pos + 'px)'
});
}, 100);
});
.container{
width: 100%;
height: 100%;
background: #000000d6;
font-size: 19px;
color: #a19999;
position: relative;
}
.contents{
margin-bottom: 15px;
border-bottom: 1px solid #424242;
padding: 20px;
visibility: hidden;
}
.center-band{
width: 98%;
height: 78px;
z-index: 200;
background: #b4b1b147;
position: fixed;
top: 50%;
}
.wrapper{
position: relative;
}
.over{
background-color: red;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="wrapper">
<div class="container">
<div class="contents"> (1) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="contents">(2) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Minima, distinctio temporibus facere, laboriosam doloribus error quaerat ipsa, non nobis rerum mollitia quibusdam quas illo a qui consequuntur consectetur deleniti saepe.</div>
<div class="contents">(3) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Unde, sed, atque. Adipisci quasi debitis, soluta praesentium distinctio impedit veritatis officia molestias culpa fuga excepturi voluptates suscipit aliquam ea unde, non!</div>
<div class="contents">(4) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Consequuntur, incidunt, harum. Perferendis ipsum, molestias nihil sequi nam nulla, aliquid ipsa numquam cum! Perferendis ut voluptates hic excepturi dolores, ipsum impedit.</div>
<div class="contents">(5) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Enim itaque debitis voluptates, reiciendis dolorum, labore eius. Illum similique ex, iusto rerum ratione minima, corporis aspernatur aliquam, itaque numquam sint enim!</div>
<div class="contents">(6) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Sint numquam totam, a aliquam veritatis porro ullam! Nostrum sint ipsum odio aperiam deserunt aut placeat dignissimos est ad, quae vitae aliquid.</div>
<div class="contents">(7) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Et quos atque enim, alias culpa quibusdam ratione, beatae non possimus, velit eaque. Optio qui saepe, earum harum beatae maxime obcaecati minima.</div>
<div class="contents">(8) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Hic id incidunt sapiente, magni, sequi ea molestiae iure maxime delectus doloribus error assumenda veritatis maiores saepe nihil neque autem similique obcaecati!</div>
<div class="contents">(9) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Voluptatum velit hic iure nam nulla natus corrupti eveniet, suscipit voluptates nostrum. Cupiditate vero ipsam alias fuga, magnam voluptas deserunt corporis non!</div>
<div class="contents">(10) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Repudiandae voluptatibus accusamus pariatur? Ipsum nobis ratione fuga, voluptates quam placeat officia odit eveniet aliquam, eaque quisquam tenetur! Exercitationem maxime vel quas!</div>
</div>
<div class="center-band"> </div>
</div>
Question: Above snippet(#snippet1) should work as same as below(#snippet2) one but without using visibility(#snippet2 Working without flashing)
#snippet2
$(function() {
var pos = 1;
var ii = 0;
var centerbandTop = $('.center-band').offset().top;
var centerbandBottom = $('.center-band').outerHeight() + centerbandTop;
var intId = setInterval(function() {
ii++;
pos = -ii;
//console.log(pos);
//if (pos )
$('.contents').each(function() {
var $content = $(this);
var contentTop = $content.offset().top;
var contentBottom = $content.outerHeight() + contentTop;
$content.css('visibility', 'hidden');
//console.log($content.position().top, centerbandTop, contentBottom);
if (centerbandBottom > contentTop && centerbandTop < contentBottom)
$content.css('visibility', 'visible');
});
$('.container').css({
// '-webkit-transform' : 'translate(0,' + pos + ')',
transform: 'translateY(' + pos + 'px)'
});
}, 100);
});
/* Styles go here */
.container{
width: 100%;
height: 100%;
background: #000000d6;
font-size: 19px;
color: #a19999;
position: relative;
}
.contents{
margin-bottom: 15px;
border-bottom: 1px solid #424242;
padding: 20px;
visibility: hidden;
}
.center-band{
width: 98%;
height: 78px;
z-index: 200;
background: #b4b1b147;
position: fixed;
top: 50%;
}
.wrapper{
position: relative;
}
.over{
background-color: red;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="wrapper">
<div class="container">
<div class="contents"> (1) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="contents">(2) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Minima, distinctio temporibus facere, laboriosam doloribus error quaerat ipsa, non nobis rerum mollitia quibusdam quas illo a qui consequuntur consectetur deleniti saepe.</div>
<div class="contents">(3) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Unde, sed, atque. Adipisci quasi debitis, soluta praesentium distinctio impedit veritatis officia molestias culpa fuga excepturi voluptates suscipit aliquam ea unde, non!</div>
<div class="contents">(4) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Consequuntur, incidunt, harum. Perferendis ipsum, molestias nihil sequi nam nulla, aliquid ipsa numquam cum! Perferendis ut voluptates hic excepturi dolores, ipsum impedit.</div>
<div class="contents">(5) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Enim itaque debitis voluptates, reiciendis dolorum, labore eius. Illum similique ex, iusto rerum ratione minima, corporis aspernatur aliquam, itaque numquam sint enim!</div>
<div class="contents">(6) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Sint numquam totam, a aliquam veritatis porro ullam! Nostrum sint ipsum odio aperiam deserunt aut placeat dignissimos est ad, quae vitae aliquid.</div>
<div class="contents">(7) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Et quos atque enim, alias culpa quibusdam ratione, beatae non possimus, velit eaque. Optio qui saepe, earum harum beatae maxime obcaecati minima.</div>
<div class="contents">(8) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Hic id incidunt sapiente, magni, sequi ea molestiae iure maxime delectus doloribus error assumenda veritatis maiores saepe nihil neque autem similique obcaecati!</div>
<div class="contents">(9) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Voluptatum velit hic iure nam nulla natus corrupti eveniet, suscipit voluptates nostrum. Cupiditate vero ipsam alias fuga, magnam voluptas deserunt corporis non!</div>
<div class="contents">(10) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Repudiandae voluptatibus accusamus pariatur? Ipsum nobis ratione fuga, voluptates quam placeat officia odit eveniet aliquam, eaque quisquam tenetur! Exercitationem maxime vel quas!</div>
</div>
<div class="center-band"> </div>
</div>
Please help me thanks in advance!!!

It is hard to understand your question, but from the code snippets you provided it looks like you need to fundamentally rethink your approach.
Your code moves the "container" div up and then computes the positions of the contained elements, but the problem is that when you hide or show an element all the other elements move in response. So when "contents 1" gets above the center band and you hide it, it stops taking up space and "contents 2" moves to where "contents 1" was. However, since "contents 1" was above the center band, now "contents 2" is above the center band and you are going to hide that, too. And so in your code, as soon as "contents 1" gets above the center band, all the contents will be hidden.
There are many ways to handle this, and the best way for your situation will probably depend on details of what you are truly trying to accomplish and which are not clear from your question. Using CSS overflow: hidden is probably the most efficient and you do not really explain what is wrong with that solution.
Another option is to adjust the position of the container to compensate for hiding the element. You also have to have some way to figure out when to show items that enter the box, which you cannot do from their position, because they are hidden. This snippet is not ideal, and there are some glitches because of margins, but it shows the concept.
$(function() {
var pos = 0;
var showNext = false;
var centerbandTop = $('.center-band').offset().top;
var centerbandBottom = $('.center-band').outerHeight() + centerbandTop;
var scroll = function() {
pos--; // move the list up one pixel
$('.contents').each(function() {
var $content = $(this);
// If the previous "contents" moved up enough
// to make room for this hidden element, show it.
if (showNext) {
$content.show();
showNext = false;
} else if ($content.is(':hidden')) // nothing to do
return;
// We have to wait until after we have shown
// the element to compute its position.
var contentTop = $content.offset().top;
var contentBottom = $content.outerHeight() + contentTop;
if (contentBottom < centerbandTop) {
// If the element has exited the top of the
// band, hide it, and move the container
// down to compensate for removing this
// element.
pos = pos + $content.outerHeight(true);
$content.hide();
} else if (contentTop > centerbandBottom) {
// If the element is below the band,
// hide it. Really this only needs to
// be done the first time through.
$content.hide();
}
// If there is room in the center band
// below this element, show the next one
showNext = contentBottom < centerbandBottom;
$('.container').css({
transform: 'translateY(' + pos + 'px)'
});
});
}
// We start with the contents "visibility: hidden"
// and all the elements displayed so we do not
// see them but still can compute their positions.
// One pass through scroll() then hides everything
// that needs to be hidden.
scroll();
// Now we can make everthing visible
$('.contents').css('visibility', 'visible');
// And now we set up the scrolling timer
var intId = setInterval(scroll, 100);
});
/* Styles go here */
.container {
width: 100%;
height: 100%;
background: #000000d6;
font-size: 19px;
color: #a19999;
position: relative;
}
.contents {
margin-bottom: 15px;
border-bottom: 1px solid #424242;
padding: 20px;
visibility: hidden;
}
.center-band {
width: 98%;
height: 78px;
z-index: 200;
background: #b4b1b147;
position: fixed;
top: 50%;
}
.wrapper {
position: relative;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="wrapper">
<div class="container">
<div class="contents"> (1) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="contents">(2) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Minima, distinctio temporibus facere, laboriosam doloribus error quaerat ipsa, non nobis rerum mollitia quibusdam quas illo a qui consequuntur consectetur deleniti saepe.</div>
<div class="contents">(3) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Unde, sed, atque. Adipisci quasi debitis, soluta praesentium distinctio impedit veritatis officia molestias culpa fuga excepturi voluptates suscipit aliquam ea unde, non!</div>
<div class="contents">(4) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Consequuntur, incidunt, harum. Perferendis ipsum, molestias nihil sequi nam nulla, aliquid ipsa numquam cum! Perferendis ut voluptates hic excepturi dolores, ipsum impedit.</div>
<div class="contents">(5) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Enim itaque debitis voluptates, reiciendis dolorum, labore eius. Illum similique ex, iusto rerum ratione minima, corporis aspernatur aliquam, itaque numquam sint enim!</div>
<div class="contents">(6) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Sint numquam totam, a aliquam veritatis porro ullam! Nostrum sint ipsum odio aperiam deserunt aut placeat dignissimos est ad, quae vitae aliquid.</div>
<div class="contents">(7) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Et quos atque enim, alias culpa quibusdam ratione, beatae non possimus, velit eaque. Optio qui saepe, earum harum beatae maxime obcaecati minima.</div>
<div class="contents">(8) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Hic id incidunt sapiente, magni, sequi ea molestiae iure maxime delectus doloribus error assumenda veritatis maiores saepe nihil neque autem similique obcaecati!</div>
<div class="contents">(9) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Voluptatum velit hic iure nam nulla natus corrupti eveniet, suscipit voluptates nostrum. Cupiditate vero ipsam alias fuga, magnam voluptas deserunt corporis non!</div>
<div class="contents">(10) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Repudiandae voluptatibus accusamus pariatur? Ipsum nobis ratione fuga, voluptates quam placeat officia odit eveniet aliquam, eaque quisquam tenetur! Exercitationem maxime vel quas!</div>
</div>
<div class="center-band"> </div>
</div>

Initially calculate the vertical beginning/ending values of all divs and store this data independently. Make all divs visible (display !== 'none')in the DOM very briefly, while using opacity to hide them, in order to calculate their heights (no way to calculate div height without attaching it to the DOM).
Also need to make all scrollable items position: absolute so that their removal doesn't reflow the items beneath them. This means javascript also needs to calculate top positions for items.
Then, whenever things change (whenever new items potentially need to be shown/hidden) check all independently stored position data against the position of the "hot zone" (the zone with which contact causes visibility).
window.onload = () => {
let positions = []; // Independently store positional data for text items
// Keep references to some useful DOM elements
let hotZone = document.getElementsByClassName('hot-zone')[0];
let scroller = document.getElementsByClassName('scroller')[0];
let scrollerHeight = scroller.getElementsByClassName('height')[0];
let items = document.getElementsByClassName('item');
let totalHeight = 0; // We'll track total height of items as we go
for (let i = 0; i < items.length; i++) {
let { height } = items[i].getBoundingClientRect();
items[i].style.top = `${Math.round(totalHeight)}px`;
items[i].style.display = 'none';
positions.push([ totalHeight, height ]);
totalHeight += height;
}
// Make sure the scroller doesn't shrink when we remove its children
scrollerHeight.style.height = `${Math.round(totalHeight)}px`;
let reevaluate = () => {
let hotRect = hotZone.getBoundingClientRect();
let scrollRect = scroller.getBoundingClientRect();
for (let i = 0; i < items.length; i++) {
let [ itemTop, itemHeight ] = positions[i];
itemTop += scrollRect.top; // Make relative to scroller
itemTop -= scroller.scrollTop; // Make relative to scroll amt
let tooHigh = itemTop + itemHeight < hotRect.top;
let tooLow = itemTop > hotRect.bottom;
let disp = (tooHigh || tooLow) ? 'none' : 'block';
if (disp !== items[i].style.display) items[i].style.display = disp;
}
};
// Immediately call `reevaluate` to initially show items
reevaluate();
// Now everything is nice so make the scroller completely opaque
document.getElementsByClassName('scroller')[0].style.opacity = '1';
// Setup listeners to call `reevaluate` when there's a possibility
// new items need to show. E.g., the "hot zone" has moved, the items
// have moved, scrolls have happened, etc.
scroller.addEventListener('scroll', reevaluate);
};
.contain {
position: fixed;
left: 0; top: 0;
width: 100%; height: 100%;
background-color: #000000;
}
.scroller {
position: relative;
left: 0; top: 0;
width: 100%; height: 100%;
overflow-x: hidden;
overflow-y: scroll;
color: #ffffff;
opacity: 0; /* Initially invisible (to avoid 1-frame flicker) */
}
.scroller > .height {
position: relative;
width: 0; height: 0; /* Invisible; lends the scroller its height */
}
.scroller > .item {
position: absolute;
left: 0; top: 0;
width: 100%;
outline: 1px solid rgba(255, 0, 0, 0.8);
}
.hot-zone {
position: absolute;
left: 0; top: 30%;
width: 100%; height: 20%;
background-color: rgba(255, 255, 255, 0.6);
box-shadow: 0 0 0 4px rgba(255, 255, 255, 0.8);
z-index: 2;
pointer-events: none;
}
<div class="contain">
<div class="hot-zone"></div>
<div class="scroller">
<div class="height"></div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">Not too much here :)</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">THIS<br/>ONE<br/>IS<br/>REALLY<br/>QUITE<br/>LONG<br/>INDEED<br/>GOOD<br/>SIR</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="item">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
</div>
</div>

So you said in your comment that
but my requirement is whichever content touches that gray band should
be shown otherwise it has to be hidden holding no width and height
From this I understand that you need a vertical text scroller. Why don't you use the gray band div as a container, with overflow hidden, and then scroll the content through it?
$(function() {
var pos = 1;
var ii = 0;
var centerbandTop = $('.center-band').offset().top;
var centerbandBottom = $('.center-band').outerHeight() + centerbandTop;
//$('.contents').hide();
var intId = setInterval(function() {
ii++;
pos = -ii;
//console.log(pos);
//if (pos )
$('.contents').each(function() {
var $content = $(this);
var contentTop = $content.offset().top;
var contentBottom = $content.outerHeight() + contentTop;
//$content.hide();
//console.log($content.position().top, centerbandTop, contentBottom);
//if (centerbandBottom > contentTop && centerbandTop < contentBottom)
//$content.show();
});
$('.container').css({
// '-webkit-transform' : 'translate(0,' + pos + ')',
transform: 'translateY(' + pos + 'px)'
});
}, 100);
});
.container{
width: 100%;
/*height: 100%;*/
background: #000000d6;
font-size: 19px;
color: #a19999;
position: relative;
}
.contents{
margin-bottom: 15px;
border-bottom: 1px solid #424242;
padding: 20px;
/*visibility: hidden;*/
}
.center-band{
width: 98%;
height: 78px;
z-index: 200;
background: #b4b1b147;
position: relative;
/*top: 50%;*/
overflow: hidden;
}
.wrapper{
position: relative;
}
.over{
background-color: red;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="wrapper">
<div>
some static text above
</div>
<div class="center-band">
<div class="container">
<div class="contents"> (1) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Necessitatibus fugit eius perferendis veritatis accusantium corporis nulla alias sed possimus quibusdam reiciendis nisi maiores inventore error, incidunt eveniet ut asperiores officiis.</div>
<div class="contents">(2) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Minima, distinctio temporibus facere, laboriosam doloribus error quaerat ipsa, non nobis rerum mollitia quibusdam quas illo a qui consequuntur consectetur deleniti saepe.</div>
<div class="contents">(3) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Unde, sed, atque. Adipisci quasi debitis, soluta praesentium distinctio impedit veritatis officia molestias culpa fuga excepturi voluptates suscipit aliquam ea unde, non!</div>
<div class="contents">(4) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Consequuntur, incidunt, harum. Perferendis ipsum, molestias nihil sequi nam nulla, aliquid ipsa numquam cum! Perferendis ut voluptates hic excepturi dolores, ipsum impedit.</div>
<div class="contents">(5) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Enim itaque debitis voluptates, reiciendis dolorum, labore eius. Illum similique ex, iusto rerum ratione minima, corporis aspernatur aliquam, itaque numquam sint enim!</div>
<div class="contents">(6) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Sint numquam totam, a aliquam veritatis porro ullam! Nostrum sint ipsum odio aperiam deserunt aut placeat dignissimos est ad, quae vitae aliquid.</div>
<div class="contents">(7) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Et quos atque enim, alias culpa quibusdam ratione, beatae non possimus, velit eaque. Optio qui saepe, earum harum beatae maxime obcaecati minima.</div>
<div class="contents">(8) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Hic id incidunt sapiente, magni, sequi ea molestiae iure maxime delectus doloribus error assumenda veritatis maiores saepe nihil neque autem similique obcaecati!</div>
<div class="contents">(9) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Voluptatum velit hic iure nam nulla natus corrupti eveniet, suscipit voluptates nostrum. Cupiditate vero ipsam alias fuga, magnam voluptas deserunt corporis non!</div>
<div class="contents">(10) Lorem ipsum dolor sit amet, consectetur adipisicing elit. Repudiandae voluptatibus accusamus pariatur? Ipsum nobis ratione fuga, voluptates quam placeat officia odit eveniet aliquam, eaque quisquam tenetur! Exercitationem maxime vel quas!</div>
</div>
</div>
<div>
some static text below
</div>
</div>

Sticky Navigation after Scrolling position

On the following website i have a navigation bar.
http://bit.do/bVXAs
I use this css code for the navigation:
z-index: 999;
position: relative;
background: #302f2f; /* Old browsers */
background: -moz-linear-gradient(top, #302f2f 0%, #000000 100%);
background: -webkit-linear-gradient(top, #302f2f 0%,#000000 100%);
background: linear-gradient(to bottom, #302f2f 0%,#000000 100%);
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#302f2f',
endColorstr='#000000',GradientType=0 ); /* IE6-9 */
box-shadow: 0px 7px 31px -5px #000;
border-bottom: 15px solid #ff9500;s
An i use a Javascript Code for the position fixed:
$(window).scroll(function () {
if ($(window).scrollTop() > 1) {
$('#navigationsleiste').css('top', $(window).scrollTop());
}
}
Now when i scroll the Navigation Bar have a space to the top of the browser window. But i dont want that space/gap. Know anyone why i have that gap/space?

The answer to 'Why the gap' has been answered in the comments I believe.
More generally, on how to fix the issue:
CSS has a position property that's very suited for your sticky menu: position: fixed. When the menu is scrolled outside of view, you change its position to fixed. Once it's back at its original location, you remove your fixed positioning.
You want to do as little as possible in a method that is executed on scroll, since it is triggered very often. Once there's too much code execution on a scroll, you loose your smooth 60fps framerate.
So what you could do is:
Make sure you always know how far the top of your sticky menu is away from the top of your window
On scroll, check if this point has been reached
Add or remove a class to your menu accordingly
Here's an example:
$(document).ready(function() {
var $doc = $(document);
var $menu = $("nav");
var menuTop = 0;
var setMenuTop = function() {
menuTop = $menu.offset().top;
}
$(window).resize(setMenuTop);
$doc.scroll(function() {
$menu.toggleClass("is-fixed", ($doc.scrollTop() > menuTop));
});
setMenuTop();
});
body {
width: 400px;
margin: 0 auto;
}
header {
height: 160px;
background: orange;
}
nav {
heigth: 40px;
background: yellow;
will-change: transform;
}
nav.is-fixed {
position: fixed;
width: 400px;
top: 0;
}
.is-fixed + article {
margin-top: 40px;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<header>header</header>
<nav>menu</nav>
<article>
<h1>content</h1>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Totam nulla enim placeat? Iure modi quasi facere provident, quidem ducimus impedit nulla harum sunt corrupti. Rem velit architecto omnis molestias, repellat.</p>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Totam nulla enim placeat? Iure modi quasi facere provident, quidem ducimus impedit nulla harum sunt corrupti. Rem velit architecto omnis molestias, repellat.</p>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Totam nulla enim placeat? Iure modi quasi facere provident, quidem ducimus impedit nulla harum sunt corrupti. Rem velit architecto omnis molestias, repellat.</p>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Totam nulla enim placeat? Iure modi quasi facere provident, quidem ducimus impedit nulla harum sunt corrupti. Rem velit architecto omnis molestias, repellat.</p>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Totam nulla enim placeat? Iure modi quasi facere provident, quidem ducimus impedit nulla harum sunt corrupti. Rem velit architecto omnis molestias, repellat.</p>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Totam nulla enim placeat? Iure modi quasi facere provident, quidem ducimus impedit nulla harum sunt corrupti. Rem velit architecto omnis molestias, repellat.</p>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Totam nulla enim placeat? Iure modi quasi facere provident, quidem ducimus impedit nulla harum sunt corrupti. Rem velit architecto omnis molestias, repellat.</p>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Totam nulla enim placeat? Iure modi quasi facere provident, quidem ducimus impedit nulla harum sunt corrupti. Rem velit architecto omnis molestias, repellat.</p>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Totam nulla enim placeat? Iure modi quasi facere provident, quidem ducimus impedit nulla harum sunt corrupti. Rem velit architecto omnis molestias, repellat.</p>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Totam nulla enim placeat? Iure modi quasi facere provident, quidem ducimus impedit nulla harum sunt corrupti. Rem velit architecto omnis molestias, repellat.</p>
</article>

Instead $(window) set it better on $(document):
$('#navigationsleiste').css('top', $(document).scrollTop());

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