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How to write a simple marquee effect with javascript

I need everyone's help. I currently need to implement a marquee effect. The yellow box needs to be scrolled up to show the name. Every time I scroll, I have to stay in the middle of the box for 1 second before continuing to scroll. I can find such an example on the Internet. , but the logic of this program is a bit difficult for me to understand for urban beginners. I wonder if anyone would like to provide a simpler and easier-to-understand writing method if I want to achieve this marquee effect?
​​Sorry, I am a beginner in the program, the current logic More complex programs are more difficult to understand.
function slideLine(box, stf, delay, speed, h) {
var slideBox = document.getElementById(box);
var delay = delay || 1000,
speed = speed || 20,
h = h || 40;
var tid = null,
pause = false;
var s = function() {
tid = setInterval(slide, speed);
};
var slide = function() {
if (pause) return;
slideBox.scrollTop += 1;
if (slideBox.scrollTop % h == 0) {
clearInterval(tid);
slideBox.appendChild(slideBox.getElementsByTagName(stf)[0]);
slideBox.scrollTop = 0;
setTimeout(s, delay);
}
};
setTimeout(s, delay);
}
slideLine("kanban_info", "p", 1000, 25, 40);
.kanban {
position: absolute;
margin: 0 auto;
width: 278px;
height: 50px;
background-color: yellow;
left: 50%;
transform: translate(-50%);
text-align: center;
line-height: 6;
}
.kanban .kenban_wrap {
height: 38px;
transform: translateY(28px);
overflow: hidden;
}
.kanban .kenban_wrap .kanban_info {
line-height: 38px;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="kanban">
<div class="kenban_wrap" id='kanban_info'>
<p class="kanban_info">Allen</p>
<p class="kanban_info">james</p>
<p class="kanban_info">jack</p>
</div>
</div>

By combining scroll-behavior with anchor tags that are programmatically clicked you can simplify it. This should be easier to understand and you can go from there, even if it might not be the best solution.
let links = document.querySelectorAll("a"); // List of links
let div = document.querySelector("div");
let index = 0;
let t = 2000; // setTimeout duration
// Change Scroll behavior to prevent the animation from the last to first list item
function scrollBeh() {
if(index == 1) {
div.style.scrollBehavior = "auto";
t = 0; // Timeout duration to 0 to prevent `1` being shown longer than other list items
} else {
div.style.scrollBehavior = "smooth";
t = 2000;
}
}
// Loop through list items
function resetInd() {
if(index < 3) {
index++;
} else {
index = 0;
}
}
function clickLinks() {
links[index].click();
resetInd();
scrollBeh();
setTimeout(clickLinks, t);
}
setTimeout(clickLinks, t);
div {
width: 200px;
height: 100px;
background-color: darkblue;
overflow: hidden;
scroll-behavior: smooth;
}
li {
height: 100px;
list-style: none;
}
a {
text-decoration: none;
color: #FFF;
font-size: 50px;
}
<div>
<ul>
<li id="one">1</li>
<li id="two">2</li>
<li id="three">3</li>
<li id="one_loop">1</li>
</ul>
</div>

Scroll a web page using Javascript whose scroll triggers at the middle of page

I have encountered some websites which has footer at the bottom and scroll actually happens when I scroll to the area above footer.
To automatically scroll those pages, but the problem with my code currently is it goes at the bottom of the page, where I directly reach footer and hence the scroll trigger which is present just above the footer does not gets triggered.
Is there any way to achieve the same?
This is what I have tried currently which I am executing from the console:
(function() {
var intervalObj = null;
var retry = 0;
var clickHandler = function() {
console.log("Clicked; stopping autoscroll");
clearInterval(intervalObj);
document.body.removeEventListener("click", clickHandler);
}
function scrollDown() {
var scrollHeight = document.body.scrollHeight,
scrollTop = document.body.scrollTop,
innerHeight = window.innerHeight,
difference = (scrollHeight - scrollTop) - innerHeight
if (difference > 0) {
window.scrollBy(0, difference);
if (retry > 0) {
retry = 0;
}
console.log("scrolling down more");
} else {
if (retry >= 3) {
console.log("reached bottom of page; stopping");
clearInterval(intervalObj);
document.body.removeEventListener("click", clickHandler);
} else {
console.log("[apparenty] hit bottom of page; retrying: " + (retry + 1));
retry++;
}
}
}
document.body.addEventListener("click", clickHandler);
intervalObj = setInterval(scrollDown, 1000);
})()
There are many websites that has this feature, to test the same one of the website which you can try is
https://www.zomato.com/bangalore/indiranagar-restaurants
Note : The question similar to this does not answer how to scroll at some mid point of page instead it takes me directly to the footer, so this is not a duplicate

Logic is to retain to the middle of the Scroller unless the page is completely loaded. We can tweak the code a little to achieve the last position of scroller. Try this:
var scrollHeight = 0,
newScrollHeight;
do {
window.scrollTo(0, document.body.scrollHeight / 2);
newScrollHeight = document.body.scrollHeight / 2;
if (newScrollHeight == scrollHeight) {
break;
} else {
scrollHeight = newScrollHeight;
}
} while (true);

Although Kumar Rishabh has already answered your question, I have another solution for this situation.
Set the domain to detect if the user scrolls to the domain.
The effect just like the website you povider . https://www.zomato.com/bangalore/indiranagar-restaurants
I do some simple example for you with pure Javascript.
Fragment core code:
// Here is domain to detect if user scroll into.
if (
triggerDomain.getBoundingClientRect().top < window.innerHeight &&
triggerDomain.getBoundingClientRect().bottom > 0
) {
if (getMore === false) {
getMore = true
// Do something you want here ....
console.info('got more !!')
Full code sample, check code snippet:
const rootElement = document.getElementById("rootDiv");
const triggerDomain = document.getElementById("triggerDomain");
let getMore = false;
function detectScrollIntoDomain() {
// Here is domain to detect if user scroll into.
if (
triggerDomain.getBoundingClientRect().top < window.innerHeight &&
triggerDomain.getBoundingClientRect().bottom > 0
) {
if (getMore === false) {
getMore = true;
// Do something you want here ....
console.info("got more !!");
setTimeout(() => {
let currentScrollTop = rootElement.scrollTop;
for (let i = 0; i < 15; i++) {
let r = Math.floor(Math.random() * 255);
let g = Math.floor(Math.random() * 255);
let b = Math.floor(Math.random() * 255);
const contentElement = document.getElementById("content");
const card = document.createElement("div");
card.className = "contentCard";
card.style.backgroundColor = `rgba(${r}, ${g}, ${b})`;
contentElement.appendChild(card);
}
rootElement.scrollTo(0, currentScrollTop);
// Don't forget to set flag to `false`.
getMore = false;
}, 200);
}
}
}
rootElement.addEventListener("scroll", detectScrollIntoDomain, {
passive: true
});
html,
body {
position: relative;
font-family: sans-serif;
padding: 0;
margin: 0;
height: 100%;
width: 100%;
}
h1,
h2 {
margin: 0;
color: aliceblue;
}
#rootDiv {
position: relative;
overflow: auto;
height: 100%;
width: 100%;
}
#header {
height: 200px;
background-color: rgb(112, 112, 112);
}
#content {
display: flex;
flex-wrap: wrap;
position: relative;
height: fit-content;
background-color: rgb(136, 136, 136);
}
#content div:first-child {
height: 600px;
width: 100%;
display: flex;
flex-direction: column;
justify-content: center;
align-items: center;
}
#triggerDomain {
position: absolute;
bottom: 0px;
outline: 1px dashed rgb(3, 25, 119);
height: 500px;
width: 100%;
background: repeating-linear-gradient(
135deg,
rgba(46, 45, 45, 0.3) 0,
rgba(46, 45, 45, 0.3) 10px,
rgba(136, 136, 136, 0.3) 10px,
rgba(136, 136, 136, 0.3) 20px
);
}
#footer {
height: 180%;
background-color: rgb(112, 112, 112);
}
.contentCard {
width: 180px;
height: 180px;
margin: 12px;
border-radius: 8px;
background-color: aquamarine;
}
<!DOCTYPE html>
<html>
<head>
<title>Parcel Sandbox</title>
<meta charset="UTF-8" />
<link rel="stylesheet" type="text/css" href="./src/styles.css"
</head>
<body>
<div id="rootDiv">
<div id="header">
<h1>Header</h1>
</div>
<div id="content">
<div>
<h2>Content</h2>
<h2>Scroll down to get more cards.</h2>
</div>
<div id="triggerDomain">
<h2>Trigger domain</h2>
</div>
</div>
<div id="footer">
<h2>Footer</h2>
</div>
</div>
<script src="src/index.js"></script>
</body>
</html>
Hope to help you !

Using setInterval to create a progress bar

I was hoping a kind soul might be able to assist.
I have a slideshow which auto-plays, my intention is to have the next button act as a visual aid, highlighting the when the next frame is coming in.
sync with the autoPlay interval.
Right now, the update func concludes too early, which is the best I have managed to do. Typically I have the clearInterval and setInterval conflicting creating shuddering animations.
What am I doing wrong?
<!doctype html>
<html lang="en">
<head>
<style>
* { box-sizing: border-box; margin: 0; padding: 0; }
.carousel_wrapper {
height: 50vh;
width: 100%;
position: relative;
}
.carousel_frame {
width: 100%; height: 100%;
}
.carousel_controls {
position: absolute;
bottom: 0;
left: 0;
}
.prev, .next {
height: 50px;
width: 100px;
background: aqua;
display: inline-block;
}
.next {
background: linear-gradient(to right, white 0%, aqua);
}
.carousel_frame:nth-child(1) {
background: red;
}
.carousel_frame:nth-child(2) {
background: blue;
}
.carousel_frame:nth-child(3) {
background: green;
}
</style>
<script>
window.addEventListener('DOMContentLoaded', () => {
const homepage_carousel = new carousel();
});
function carousel() {
const carousel = document.getElementsByClassName('.carousel_wrapper')[0];
const frames = [...document.getElementsByClassName('carousel_frame')];
const prev_button = document.getElementsByClassName('prev')[0];
const next_button = document.getElementsByClassName('next')[0];
this.frameIndex = 1;
prev_button.addEventListener('click', () => {
this.resetPlay();
this.move(-1);
})
next_button.addEventListener('click', () => {
this.resetPlay();
this.move(+1);
})
this.hideAll = () => {
frames.forEach((f) => {
f.style.display = 'none';
});
}
this.show = () => {
this.hideAll();
frames[this.frameIndex - 1].style.display = 'block';
this.update_bg();
}
this.move = (amount) => {
this.frameIndex += amount;
this.frameIndex = (this.frameIndex > frames.length ? 1 : (this.frameIndex < 1) ? frame.lengh : this.frameIndex);
this.show();
}
this.update_bg = () => {
let w = 1;
let test = setInterval(adjust, 10);
function adjust() {
if (w >= 100) {
clearInterval(test);
w = 0;
} else {
w++;
next_button.style.backgroundImage = `linear-gradient(to right, white ${w}%, aqua)`
}
}
setInterval(adjust, 3000);
}
this.autoPlay = () => {
this.move(+1)
this.update_bg();
}
this.resetPlay = () => {
// clearInterval(timer);
// timer = setInterval(this.autoPlay(), 4000);
}
this.show();
const timer = setInterval(this.autoPlay, 3000);
}
</script>
</head>
<body>
<div class='carousel_wrapper'>
<div class='carousel_frame'>
<span>Headline</span>
<span>Description</span>
<span>CTA</span>
</div>
<div class='carousel_frame'>
<span>Headline</span>
<span>Description</span>
<span>CTA</span>
</div>
<div class='carousel_frame'>
<span>Headline</span>
<span>Description</span>
<span>CTA</span>
</div>
<div class='carousel_controls'>
<span class='prev'>Previous</span>
<span class='next'>
Next
</span>
</div>
</div>
</body>
</html>

JavaScript - How can I access the siblings of an event.currentTarget?

I created a basic voting system for a comment ratings bar. I'm trying to access the previous Sibling Element to update the votes but it's not working properly. IAre you're supposed to use event.currentTarget or event.target? Where did I go wrong? Thank you.
https://jsfiddle.net/donfontaine12/bm9njcLt/46/#&togetherjs=qocecyJqyy
HTML
<div id="comment_ratings_bar">
<div id="comment_rating_sign">+</div>
<div id="comment_rating_num">0</div>
<div id="comment_rating_percentage">[100.00%] </div>
<div class="green_up_arrow"></div>
<div class="red_down_arrow"></div>
</div>
<div id="comment_ratings_bar">
<div id="comment_rating_sign">+</div>
<div id="comment_rating_num">0</div>
<div id="comment_rating_percentage">[100.00%] </div>
<div class="green_up_arrow"></div>
<div class="red_down_arrow"></div>
</div>
<div id="comment_ratings_bar">
<div id="comment_rating_sign">+</div>
<div id="comment_rating_num">0</div>
<div id="comment_rating_percentage">[100.00%] </div>
<div class="green_up_arrow"></div>
<div class="red_down_arrow"></div>
</div>
<div id="comment_ratings_bar">
<div id="comment_rating_sign">+</div>
<div id="comment_rating_num">0</div>
<div id="comment_rating_percentage">[100.00%] </div>
<div class="green_up_arrow"></div>
<div class="red_down_arrow"></div>
</div>
CSS
#comment_ratings_bar {
width: 30%;
margin: 0px 20px;
padding: 0px 20px;
font-size: 110%;
font-weight: bolder;
font-family: 'B612 Mono', monospace;
color: lime;
background-color: black;
border: 0px solid black;
display: flex;
flex-direction: row;
justify-content: center;
}
.green_up_arrow {
display: flex;
flex-direction: row;
width: 0;
height: 0;
border-left: 5px solid transparent;
border-right: 5px solid transparent;
border-bottom: 10px solid lime;
cursor: pointer;
margin: 0em 0.25em;
}
.red_down_arrow {
display: flex;
flex-direction: row;
width: 0;
height: 0;
border-left: 5px solid transparent;
border-right: 5px solid transparent;
border-top: 10px solid red;
cursor: pointer;
margin: 0em 0.25em;
}
JavaScript
window.onload = function() {
let commentUpvotes = 0;
let commentDownvotes = 0;
let totalCommentVotes = commentUpvotes + commentDownvotes;
let commentRatingsBarAll = document.querySelectorAll("#comment_ratings_bar");
for (let c of commentRatingsBarAll) {
c.lastElementChild.previousElementSibling.addEventListener("click", updateCommentVotes);
c.lastElementChild.addEventListener("click", updateCommentVotes);
}
function updateCommentVotes(e) {
let siblings = getSiblings(e);
let sign = siblings[0].textContent;
let number = siblings[1].textContent;
let percentage = siblings[2].textContent;
if (sign && number && percentage) {
let actualNumber = parseFloat(number.replace(/,/g, ''));
if (e.target.className == "green_up_arrow") {
actualNumber++; commentUpvotes++; totalCommentVotes++;
} else {
actualNumber--; commentDownvotes++; totalCommentVotes++;
}
if (actualNumber < 0) { sign.replace("+", ""); }
percentage = "["
+ parseFloat((commentUpvotes / totalCommentVotes) * 100).toFixed(2) +"%]";
number = actualNumber.toLocaleString();
}
}
function getSiblings(element) {
if (element) {
let siblings = [];
let sibling = element.parentNode.firstElementChild;
while(sibling) {
if (sibling.nodeType === 1 && sibling !== element) {
siblings.push(sibling);
sibling = sibling.nextElementSibling;
}
}
return siblings;
}
}
}

Everything's working but inside the updateCommentVotes function, I should have been referencing the actual divs containing the textContent instead of the local variables (sign, number & percentage).
EDIT: It's a partial fix, I need each individual comment bar to refer to its own sign, number and percentage. It seems they all share the same number values. Any tips are appreciated. Although, I believe its because I hard coded the values from siblings. Thank you.
Check the code here: https://jsfiddle.net/donfontaine12/bm9njcLt/46/#
JavaScript
window.onload = function() {
let commentUpvotes = 0;
let commentDownvotes = 0;
let totalCommentVotes = commentUpvotes + commentDownvotes;
let commentRatingsBarAll = document.querySelectorAll("#comment_ratings_bar");
for (let c of commentRatingsBarAll) {
c.lastElementChild.previousElementSibling.addEventListener("click", updateCommentVotes);
c.lastElementChild.addEventListener("click", updateCommentVotes);
}
function updateCommentVotes(e) {
let siblings = getSiblings(e);
let sign = siblings[0].textContent;
let number = siblings[1].textContent;
let percentage = siblings[2].textContent;
if (sign && number && percentage) {
let actualNumber = parseFloat(number.replace(/,/g, ''));
if (e.target.className == "green_up_arrow") {
actualNumber++; commentUpvotes++; totalCommentVotes++;
} else {
actualNumber--; commentDownvotes++; totalCommentVotes++;
}
if (actualNumber < 0) { siblings[0].textContent.replace("+", ""); }
siblings[2].textContent = "["
+ parseFloat((commentUpvotes / totalCommentVotes) * 100).toFixed(2) +"%]";
siblings[1].textContent = actualNumber.toLocaleString();
}
}
function getSiblings(element) {
let siblings = [];
let sibling = element.target.parentNode.firstElementChild;
while(sibling) {
if (sibling.nodeType === 1 && sibling !== element) {
siblings.push(sibling);
sibling = sibling.nextElementSibling;
}
}
return siblings;
}
}

image script not displaying

I have this code and the problem is the "main" and "left/right" image are not being displayed. I have gone through the entire logic and can't figure out what is wrong.
The code works if I replace else with else if(flag===1 && child[I].id=="left" || child[I].id=="right")
Expected output:
movement of mouse should change the image, this change is determined by the height of the <body> element.
Output getting:
only one image is displayed and does not changes no mater where I move my mouse.
[ also changing event from "mouseover" to "mousemove" does not help ]
so why isn't it working when I remove it, shouldn't at least "main" work??
PS: I'm unable to provide an image, please find another one.
'use strict';
(function() {
var wlen = screen.availWidth;
var whet = screen.availHeight;
var last = {};
var chk = 3;
var eye = document.getElementsByClassName("eyes");
var build = function(ele) {
if (ele.previousElementSibling !== null) ele.previousElementSibling.style = "none";
last = ele.style;
last.display = "block";
}
var anite = function() {
var x = event.screenX;
var y = event.screenY;
last.display = "none";
var child;
var flag;
y < whet / 3 ? flag = 2 : (y > 2 * whet / 3) ? flag = 0 : flag = 1;
x < wlen / 2 ? child = eye[1].childNodes : child = eye[0].childNodes;
for (let i = 0; i < child.length; i++) {
if (child[i].id) {
if (child[i].id == "main" && flag === 0) {
build(child[i]);
} else if (child[i].id.search(/a/i) === 0 && flag === 2) {
build(child[i]);
} else {
build(child[i]);
}
}
}
}
document.addEventListener("mouseover", anite, false);
})()
html,body {
height: 100%;
}
body {
display: flex;
align-items: center;
}
main {
width: 100%;
overflow: hidden;
}
.eyes {
width:50%;
float: left;
height: 300px;
}
#main {
background: url('eyes.png') no-repeat 0 0;
width: 1000px;
height: 254px;
display:none;
}
#left {
background: url('eyes.png') no-repeat 0 -254px;
width: 1000px;
height: 254px;
display:none;
}
#aLeft {
background: url('eyes.png') no-repeat 0 -508px;
width: 1000px;
height: 254px;
display:none;
}
#right {
background: url('eyes.png') no-repeat 0 -762px;
width: 1000px;
height: 254px;
display:none;
}
#aRight {
background: url('eyes.png') no-repeat 0 -1016px;
width: 1000px;
height: 280px;
display:none;
}
<html>
<head>
<title>Student Details</title>
</head>
<body>
<main>
<div class="eyes">
<!-- <img src="eyes.png" alt="eyes"> -->
<p id="main"></p>
<p id="right"></p>
<p id="aRight"></p>
</div>
<div class="eyes">
<p id="main"></p>
<p id="left"></p>
<p id="aLeft"></p>
</div>
</main>
</body>
</html>