I'm currently trying to implement a horizontal scroll. It works, but I'm trying to make some changes:
Since the web-app is a one screener and solely consists of this horizontal scroll, I'd like to convert vertical scroll to horizontal scroll. But how? What's the approach?
I've tried the following js library, but this one solely works if overflow is set to visible, which kind of breaks my app.
My horizontal scroll:
<div class="scroll-container align-self-center d-flex">
<div class="cart-container align-self-center" *ngFor="let cart of carts; let i = index">
<div class="cart-item cursor-hover position-relative" [ngStyle]="{'background-image': 'url(' + cart.image + ')'}" [class.cart-item-even]="i % 2 !== 0"
(mouseenter)="changeBackgroundColor(i)">
<h1 class="hover-title">{{cart.title}}</h1>
</div>
</div>
</div>
CSS:
.cart-item {
background-size: cover;
background-position: center;
background-repeat: no-repeat;
width: 22.5vw;
height: 65vh;
}
.cart-item-even {
height: 55vh;
width: 20vw;
}
.cart-container {
display: inline-block;
}
.scroll-container {
padding: 0 15vw 0 15vw;
box-sizing: border-box;
overflow: auto;
white-space: nowrap;
}
//ts
scroll = () => {
function scrollHorizontally(e) {
e = window.event || e;
var delta = Math.max(-1, Math.min(1, (e.wheelDelta || -e.detail)));
document.getElementById('main-content').scrollLeft -= (delta*40); // Multiplied by 40
e.preventDefault();
}
if (document.getElementById('main-content').addEventListener) {
// IE9, Chrome, Safari, Opera
document.getElementById('main-content').addEventListener("mousewheel", scrollHorizontally, false);
// Firefox
document.getElementById('main-content').addEventListener("DOMMouseScroll", scrollHorizontally, false);
} else {
// IE 6/7/8
// document.getElementById('main-content').attachEvent("onmousewheel", scrollHorizontally);
}
}
ngOnInit(): void {
this.scroll();
}
For an horizontal scrolling you can do whatever you want inside a div like that :
.mydiv {
overflow-x: scroll;
display: -webkit-box;
}
I hope this gonna help you :)
Related
I have a flex box to center 3 divs in the screen. all the three are wrapped around a flex container that has justify-content: center which centers them in the screen. However, since I am using animation and each div is being added one after another, the first div gets added at the center instead of the beginning, the second gets added such that both of the first and second are centered, and when the third is added, all of them are aligned such that the second div is exactly in the middle of the screen. I want to change that such that each div gets added in-place from left to right while all are centered in the screen.
React code:
function foo() {
const [items, set] = React.useState([]);
const transitions = useTransition(items, (item) => item.key, {
from: { transform: "translate3d(0,-40px,0)" },
enter: { transform: "translate3d(0,0px,0)" },
leave: { transform: "translate3d(0,-40px,0)" },
});
React.useEffect(() => {
for (let i = 0; i < rows.length; i++) {
setTimeout(() => {
set((items) => {
const newItems = [...items];
newItems.push({ key: i, code: rows[i] });
return newItems;
});
}, 1000 * i);
}
}, []);
return (
<center>
<div class="flex-container">
{transitions.map(({ item, props, key }) => {
return (
<animated.div key={key} style={props} class="flex-item">
{item.code}
</animated.div>
);
})}
</div>
</center>
);
}
Styling:
.flex-container {
height: 50vh;
display: flex;
justify-content: center;
img{
width: 20%;
text-align: center;
}
}
.flex-item {
flex-basis: 14%;
align-self: center;
margin: 12px;
h4{
font-family: Lato;
font-weight:700;
color: white;
}
p{
color: white;
font-family: Lato;
}
}
Changing center to flex-start shifts everything to the beginning:
Adding fixed width doesn't work as well:
To solve your problem, simply align the cards the way you want them to look after they move, then apply the following CSS:
.card {
position: relative;
top: -100px;
}
If -100px is not enough, try -200px. The goal is that the cards will be off-screen at the top. Upon whatever action you desire, whether it be clicking a button like in my snippet below, or perhaps on page load, change the "top" property to 0, and it will place the card where it belongs in the normal flow of the page.
I additionally use the setTimeout function to delay each subsequent card, and the transition property to animate the movement smoothly since it seems like that is your desired goal.
const left = document.getElementById("left");
const center = document.getElementById("center");
const right = document.getElementById("right");
function foo() {
left.style.top = "0";
setTimeout(function() {
center.style.top = "0";
setTimeout(function() {
right.style.top = "0";
}, 500)
}, 500)
}
#container {
display: flex;
justify-content: center;
}
#container>* {
width: 100px;
height: 50px;
background: red;
margin: 0 0.5em;
position: relative;
top: -100px;
transition: top 1s ease-in-out;
}
button {
margin: auto;
}
<div id="container">
<div id="left"></div>
<div id="center"></div>
<div id="right"></div>
</div>
<button onclick="foo()" id="click-me">Click me!</button>
I have a search bar which would like to display onto the header on scroll, a great example is like the one on this site: https://www.indiamart.com/
Approach 1 - A simple way to do this would be to detect a scroll & add and remove a class that contains display: none;
You can have an event listener -
window.addEventListener('scroll', function() {
if( window.scrollY !== 0) {
document.getElementById('searchBar').classList.add('scrolled');
} else {
document.getElementById('searchBar').classList.remove('scrolled');
}
});
With the CSS -
.noScroll
{
background: yellow;
position:fixed;
height: 50px; /*Whatever you want*/
width: 100%; /*Whatever you want*/
top:0;
left:0;
display:none;
}
/*Use this class when you want your content to be shown after some scroll*/
.scrolled
{
display: block !important;
}
.parent {
/* something to ensure that the parent container is scrollable */
height: 200vh;
}
And the html would be -
<div class="parent">
<div class ='noScroll' id='searchBar'>Content you want to show on scroll</div>
</div>
Here's a JSFiddle of the same - https://jsfiddle.net/kecnrh3g/
Approach 2 -
Another simple approach would be
<script>
let prevScrollpos = window.pageYOffset;
window.onscroll = function() {
let currentScrollPos = window.pageYOffset;
if (prevScrollpos > currentScrollPos) {
document.getElementById('searchBar').style.top = '-50px';
} else {
document.getElementById('searchBar').style.top = '0';
}
prevScrollpos = currentScrollPos;
}
</script>
with the html -
<div class="parent">
<div id ='searchBar'>Content you want to show on scroll</div>
</div>
and css
#searchBar {
background: yellow;
position: fixed;
top: 0;
left: 0;
height: 50px;
width: 100%;
display: block;
transition: top 0.3s;
}
.parent {
height: 200vh;
}
Here's a JSFiddle of the same - https://jsfiddle.net/0tkedcns/1/
From the same example, the idea is only to show/hide once user scroll the page using inline css display property, you can do the same or at least provide a code sample so we can help you!
HTML
<div class="search-bar">
<div class="sticky-search">
Sticky Search: <input type="text" value="search" />
</div>
</div>
CSS
.sticky-search {
display:none;
position:fixed;
top:0px;
left:0px;
right:0px;
background:blue;
padding:10px;
}
JS
var searchHeight = $(".search-bar").outerHeight();
var offset = $(".search-bar").offset().top;
var totalHeight = searchHeight + offset;
console.log(totalHeight);
$(window).scroll(function(){
if($(document).scrollTop() >= totalHeight) {
$('.sticky-search').show();
} else {
$('.sticky-search').hide();
}
});
I've got a header that I want to disappear (move above the top of the browser screen) when the user scrolls down, then when the user scrolls back up I want the header to reappear (move back down) and also to gain a solid white background behind it.
All of this is working fine, but then I want the white background to be removed if the user scrolls back up to the very top of the page again (so it's just the header visible but with no white background).
I've cobbled together the code for this, and it's pretty much working - but, for some reason, in certain circumstances, the white background isn't being removed?!
It seems to be if you've scrolled back up enough to make the header reappear with the white background, but not all the way top the top, and then scroll the rest of the way then the white background doesn't disappear for some reason.
Sorry, I've probably not explained that very well, but here's my code. If someone is able to replicate the bug I'm getting and offer an explanation I'd be very grateful!
Thanks
// Hide Header on on scroll down
var didScroll;
var lastScrollTop = 0;
var delta = 30;
var navbarHeight = $('header').outerHeight();
$(window).scroll(function(event){
didScroll = true;
});
setInterval(function() {
if (didScroll) {
hasScrolled();
didScroll = false;
}
}, 30);
function hasScrolled() {
var st = $(this).scrollTop();
// Make sure they scroll more than delta
if(Math.abs(lastScrollTop - st) <= delta)
return;
// If they scrolled down and are past the navbar, add class .nav-up.
// This is necessary so you never see what is "behind" the navbar.
if (st > lastScrollTop && st > navbarHeight){
// Scroll Down
$('header').removeClass('header-down').addClass('header-up').removeClass('header-solid');
} else {
// Scroll Up
if(st + $(window).height() < $(document).height()) {
$('header').removeClass('header-up').addClass('header-down').addClass('header-solid');
}
}
lastScrollTop = st;
};
$(function () {
$(window).scroll(function () {
var top_offset = $(window).scrollTop();
if (top_offset == 0) {
$('header').removeClass('header-solid');
}
})
});
body {
margin: 0;
background: url('https://images.unsplash.com/3/doctype-hi-res.jpg?ixid=MXwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHw%3D&ixlib=rb-1.2.1&auto=format&fit=crop&w=2246&q=80');
background-size: cover;
}
.wrapper {
width: 100%;
height: 3000px;
}
header {
display: flex;
width: 100%;
padding: 20px 50px;
position: fixed;
box-sizing: border-box;
transition: 300ms all ease-in-out;
margin-top: 0px;
}
.header-logo {
width: 200px;
}
.header-nav {
flex-grow: 1;
text-align: center;
}
.header-socials {
width: 200px;
text-align: right;
}
.header-up {
margin-top: -60px;
}
.header-down {
margin-top: 0px;
}
.header-solid {
background-color: #FFFFFF;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="wrapper">
<header class="header-down">
<div class="header-logo">
<img src="#" class="img-header-logo"/>
</div>
<div class="header-nav">
One Two Three Four Five
</div>
<div class="header-socials">
Social Links
</div>
</header>
</div>
Here is an example chat app ->
The idea here is to have the .messages-container take up as much of the screen as it can. Within .messages-container, .scroll holds the list of messages, and in case there are more messages then the size of the screen, scrolls.
Now, consider this case:
The user scrolls to the bottom of the conversation
The .text-input, dynamically gets bigger
Now, instead of the user staying scrolled to the bottom of the conversation, the text-input increases, and they no longer see the bottom.
One way to fix it, if we are using react, calculate the height of text-input, and if anything changes, let .messages-container know
componentDidUpdate() {
window.setTimeout(_ => {
const newHeight = this.calcHeight();
if (newHeight !== this._oldHeight) {
this.props.onResize();
}
this._oldHeight = newHeight;
});
}
But, this causes visible performance issues, and it's sad to be passing messages around like this.
Is there a better way? Could I use css in such a way, to express that when .text-input-increases, I want to essentially shift up all of .messages-container
2:nd revision of this answer
Your friend here is flex-direction: column-reverse; which does all you ask while align the messages at the bottom of the message container, just like for example Skype and many other chat apps do.
.chat-window{
display:flex;
flex-direction:column;
height:100%;
}
.chat-messages{
flex: 1;
height:100%;
overflow: auto;
display: flex;
flex-direction: column-reverse;
}
.chat-input { border-top: 1px solid #999; padding: 20px 5px }
.chat-input-text { width: 60%; min-height: 40px; max-width: 60%; }
The downside with flex-direction: column-reverse; is a bug in IE/Edge/Firefox, where the scrollbar doesn't show, which your can read more about here: Flexbox column-reverse and overflow in Firefox/IE
The upside is you have ~ 90% browser support on mobile/tablets and ~ 65% for desktop, and counting as the bug gets fixed, ...and there is a workaround.
// scroll to bottom
function updateScroll(el){
el.scrollTop = el.scrollHeight;
}
// only shift-up if at bottom
function scrollAtBottom(el){
return (el.scrollTop + 5 >= (el.scrollHeight - el.offsetHeight));
}
In the below code snippet I've added the 2 functions from above, to make IE/Edge/Firefox behave in the same way flex-direction: column-reverse; does.
function addContent () {
var msgdiv = document.getElementById('messages');
var msgtxt = document.getElementById('inputs');
var atbottom = scrollAtBottom(msgdiv);
if (msgtxt.value.length > 0) {
msgdiv.innerHTML += msgtxt.value + '<br/>';
msgtxt.value = "";
} else {
msgdiv.innerHTML += 'Long long content ' + (tempCounter++) + '!<br/>';
}
/* if at bottom and is IE/Edge/Firefox */
if (atbottom && (!isWebkit || isEdge)) {
updateScroll(msgdiv);
}
}
function resizeInput () {
var msgdiv = document.getElementById('messages');
var msgtxt = document.getElementById('inputs');
var atbottom = scrollAtBottom(msgdiv);
if (msgtxt.style.height == '120px') {
msgtxt.style.height = 'auto';
} else {
msgtxt.style.height = '120px';
}
/* if at bottom and is IE/Edge/Firefox */
if (atbottom && (!isWebkit || isEdge)) {
updateScroll(msgdiv);
}
}
/* fix for IE/Edge/Firefox */
var isWebkit = ('WebkitAppearance' in document.documentElement.style);
var isEdge = ('-ms-accelerator' in document.documentElement.style);
var tempCounter = 6;
function updateScroll(el){
el.scrollTop = el.scrollHeight;
}
function scrollAtBottom(el){
return (el.scrollTop + 5 >= (el.scrollHeight - el.offsetHeight));
}
html, body { height:100%; margin:0; padding:0; }
.chat-window{
display:flex;
flex-direction:column;
height:100%;
}
.chat-messages{
flex: 1;
height:100%;
overflow: auto;
display: flex;
flex-direction: column-reverse;
}
.chat-input { border-top: 1px solid #999; padding: 20px 5px }
.chat-input-text { width: 60%; min-height: 40px; max-width: 60%; }
/* temp. buttons for demo */
button { width: 12%; height: 44px; margin-left: 5%; vertical-align: top; }
/* begin - fix for hidden scrollbar in IE/Edge/Firefox */
.chat-messages-text{ overflow: auto; }
#media screen and (-webkit-min-device-pixel-ratio:0) {
.chat-messages-text{ overflow: visible; }
/* reset Edge as it identifies itself as webkit */
#supports (-ms-accelerator:true) { .chat-messages-text{ overflow: auto; } }
}
/* hide resize FF */
#-moz-document url-prefix() { .chat-input-text { resize: none } }
/* end - fix for hidden scrollbar in IE/Edge/Firefox */
<div class="chat-window">
<div class="chat-messages">
<div class="chat-messages-text" id="messages">
Long long content 1!<br/>
Long long content 2!<br/>
Long long content 3!<br/>
Long long content 4!<br/>
Long long content 5!<br/>
</div>
</div>
<div class="chat-input">
<textarea class="chat-input-text" placeholder="Type your message here..." id="inputs"></textarea>
<button onclick="addContent();">Add msg</button>
<button onclick="resizeInput();">Resize input</button>
</div>
</div>
Side note 1: The detection method is not fully tested, but it should work on newer browsers.
Side note 2: Attach a resize event handler for the chat-input might be more efficient then calling the updateScroll function.
Note: Credits to HaZardouS for reusing his html structure
You just need one CSS rule set:
.messages-container, .scroll {transform: scale(1,-1);}
That's it, you're done!
How it works: First, it vertically flips the container element so that the top becomes the bottom (giving us the desired scroll orientation), then it flips the content element so that the messages won't be upside down.
This approach works in all modern browsers. It does have a strange side effect, though: when you use a mouse wheel in the message box, the scroll direction is reversed. This can be fixed with a few lines of JavaScript, as shown below.
Here's a demo and a fiddle to play with:
//Reverse wheel direction
document.querySelector('.messages-container').addEventListener('wheel', function(e) {
if(e.deltaY) {
e.preventDefault();
e.currentTarget.scrollTop -= e.deltaY;
}
});
//The rest of the JS just handles the test buttons and is not part of the solution
send = function() {
var inp = document.querySelector('.text-input');
document.querySelector('.scroll').insertAdjacentHTML('beforeend', '<p>' + inp.value);
inp.value = '';
inp.focus();
}
resize = function() {
var inp = document.querySelector('.text-input');
inp.style.height = inp.style.height === '50%' ? null : '50%';
}
html,body {height: 100%;margin: 0;}
.conversation {
display: flex;
flex-direction: column;
height: 100%;
}
.messages-container {
flex-shrink: 10;
height: 100%;
overflow: auto;
}
.messages-container, .scroll {transform: scale(1,-1);}
.text-input {resize: vertical;}
<div class="conversation">
<div class="messages-container">
<div class="scroll">
<p>Message 1<p>Message 2<p>Message 3<p>Message 4<p>Message 5
<p>Message 6<p>Message 7<p>Message 8<p>Message 9<p>Message 10<p>Message 11<p>Message 12<p>Message 13<p>Message 14<p>Message 15<p>Message 16<p>Message 17<p>Message 18<p>Message 19<p>Message 20
</div>
</div>
<textarea class="text-input" autofocus>Your message</textarea>
<div>
<button id="send" onclick="send();">Send input</button>
<button id="resize" onclick="resize();">Resize input box</button>
</div>
</div>
Edit: thanks to #SomeoneSpecial for suggesting a simplification to the scroll code!
Please try the following fiddle - https://jsfiddle.net/Hazardous/bypxg25c/. Although the fiddle is currently using jQuery to grow/resize the text area, the crux is in the flex related styles used for the messages-container and input-container classes -
.messages-container{
order:1;
flex:0.9 1 auto;
overflow-y:auto;
display:flex;
flex-direction:row;
flex-wrap:nowrap;
justify-content:flex-start;
align-items:stretch;
align-content:stretch;
}
.input-container{
order:2;
flex:0.1 0 auto;
}
The flex-shrink value is set to 1 for .messages-container and 0 for .input-container. This ensures that messages-container shrinks when there is a reallocation of size.
I've moved text-input within messages, absolute positioned it to the bottom of the container and given messages enough bottom padding to space accordingly.
Run some code to add a class to conversation, which changes the height of text-input and bottom padding of messages using a nice CSS transition animation.
The JavaScript runs a "scrollTo" function at the same time as the CSS transition is running to keep the scroll at the bottom.
When the scroll comes off the bottom again, we remove the class from conversation
Hope this helps.
https://jsfiddle.net/cnvzLfso/5/
var doScollCheck = true;
var objConv = document.querySelector('.conversation');
var objMessages = document.querySelector('.messages');
var objInput = document.querySelector('.text-input');
function scrollTo(element, to, duration) {
if (duration <= 0) {
doScollCheck = true;
return;
}
var difference = to - element.scrollTop;
var perTick = difference / duration * 10;
setTimeout(function() {
element.scrollTop = element.scrollTop + perTick;
if (element.scrollTop === to) {
doScollCheck = true;
return;
}
scrollTo(element, to, duration - 10);
}, 10);
}
function resizeInput(atBottom) {
var className = 'bigger',
hasClass;
if (objConv.classList) {
hasClass = objConv.classList.contains(className);
} else {
hasClass = new RegExp('(^| )' + className + '( |$)', 'gi').test(objConv.className);
}
if (atBottom) {
if (!hasClass) {
doScollCheck = false;
if (objConv.classList) {
objConv.classList.add(className);
} else {
objConv.className += ' ' + className;
}
scrollTo(objMessages, (objMessages.scrollHeight - objMessages.offsetHeight) + 50, 500);
}
} else {
if (hasClass) {
if (objConv.classList) {
objConv.classList.remove(className);
} else {
objConv.className = objConv.className.replace(new RegExp('(^|\\b)' + className.split(' ').join('|') + '(\\b|$)', 'gi'), ' ');
}
}
}
}
objMessages.addEventListener('scroll', function() {
if (doScollCheck) {
var isBottom = ((this.scrollHeight - this.offsetHeight) === this.scrollTop);
resizeInput(isBottom);
}
});
html,
body {
height: 100%;
width: 100%;
background: white;
}
body {
margin: 0;
padding: 0;
}
.conversation {
display: flex;
flex-direction: column;
justify-content: space-between;
height: 100%;
position: relative;
}
.messages {
overflow-y: scroll;
padding: 10px 10px 60px 10px;
-webkit-transition: padding .5s;
-moz-transition: padding .5s;
transition: padding .5s;
}
.text-input {
padding: 10px;
-webkit-transition: height .5s;
-moz-transition: height .5s;
transition: height .5s;
position: absolute;
bottom: 0;
height: 50px;
background: white;
}
.conversation.bigger .messages {
padding-bottom: 110px;
}
.conversation.bigger .text-input {
height: 100px;
}
.text-input input {
height: 100%;
}
<div class="conversation">
<div class="messages">
<p>
This is a message content
</p>
<p>
This is a message content
</p>
<p>
This is a message content
</p>
<p>
This is a message content
</p>
<p>
This is a message content
</p>
<p>
This is a message content
</p>
<p>
This is a message content
</p>
<p>
This is a message content
</p>
<p>
This is a message content
</p>
<p>
This is a message content
</p>
<p>
This is a message content
</p>
<p>
This is a message content
</p>
<p>
This is a message content
</p>
<p>
This is a message content
</p>
<p>
This is the last message
</p>
<div class="text-input">
<input type="text" />
</div>
</div>
</div>
You write;
Now, consider this case:
The user scrolls to the bottom of the conversation
The .text-input, dynamically gets bigger
Wouldn't the method that dynamically sets the .text-input be the logical place to fire this.props.onResize().
To whom it may concern,
The answers above did not suffice my question.
The solution I found was to make my innerWidth and innerHeight variable constant - as the innerWidth of the browser changes on scroll to adapt for the scrollbar.
var innerWidth = window.innerWidth
var innerHeight = window.innerHeight
OR FOR REACT
this.setState({width: window.innerWidth, height: window.innerHeight})
In other words, to ignore it, you must make everything constant as if it were never scrolling. Do remember to update these on Resize / Orientation Change !
IMHO current answer is not a correct one:
1/ flex-direction: column-reverse; reverses the order of messages - I didn't want that.
2/ javascript there is also a bit hacky and obsolete
If you want to make it like a PRO use spacer-box which has properties:
flex-grow: 1;
flex-basis: 0;
and is located above messages. It pushes them down to the chat input.
When user is typing new messages and input height is growing the scrollbar moves up, but when the message is sent (input is cleared) scrollbar is back at bottom.
Check my snippet:
body {
background: #ccc;
}
.chat {
display: flex;
flex-direction: column;
width: 300px;
max-height: 300px;
max-width: 90%;
background: #fff;
}
.spacer-box {
flex-basis: 0;
flex-grow: 1;
}
.messages {
display: flex;
flex-direction: column;
overflow-y: auto;
flex-grow: 1;
padding: 24px 24px 4px;
}
.footer {
padding: 4px 24px 24px;
}
#chat-input {
width: 100%;
max-height: 100px;
overflow-y: auto;
border: 1px solid pink;
outline: none;
user-select: text;
white-space: pre-wrap;
overflow-wrap: break-word;
}
<div class="chat">
<div class="messages">
<div class="spacer-box"></div>
<div class="message">1</div>
<div class="message">2</div>
<div class="message">3</div>
<div class="message">4</div>
<div class="message">5</div>
<div class="message">6</div>
<div class="message">7</div>
<div class="message">8</div>
<div class="message">9</div>
<div class="message">10</div>
<div class="message">11</div>
<div class="message">12</div>
<div class="message">13</div>
<div class="message">14</div>
<div class="message">15</div>
<div class="message">16</div>
<div class="message">17</div>
<div class="message">18</div>
</div>
<div class="footer">
<div contenteditable role="textbox" id="chat-input"></div>
</div>
<div>
Hope I could help :)
Cheers
I am using this for my header that changes in a one page scroll up and down page. I noticed that it's not responsive so i am asking you if you maybe know a way to make that responsive. Like changing the 0-690 into a percentage so that it will work on mobile and also on a tv screen.
HTML
<div class="header header-1" data-visible-range="0-690">Portfolio</div>
<div class="header header-2" data-visible-range="691-2100">Services</div>
<div class="header header-3" data-visible-range="2101-">Contact</div>
CSS
.header-1 {
background-color:dimgray;
display: block;
}
.header-2 {
background-color:dimgray;
}
.header-3 {
background-color:dimgray;
}
.header {
position: fixed;
top: 0;
left: 0;
height:8vmax;
width: 100%;
display: none;
visibility:hidden;
transition: visibility .4s, opacity .4s ease-in-out;opacity:0;
font-size:4vmax;padding:1.58vmax;color:white;
}
What if, instead of basing it off pixels, you just checked to see if an element hit the top of the page, and then changed the header?
We'll call these elements "triggers." See my code below for an example of how they work.
let updateHeader = () => {
let scrollTop = $(window).scrollTop(),
triggerTitle = "Hi";
$('.trigger').each((i, el) => {
let topPos = $(el).offset().top,
distance = topPos - scrollTop;
if (distance < 0)
triggerTitle = $(el).data('title');
});
$('header h2').text(triggerTitle);
}
$(window).scroll(updateHeader);
$(window).on('touchmove', updateHeader);
body {
margin: 0;
}
#container {
height: 1000px;
}
header {
width: 100%;
position: fixed;
top: 0;
background-color: red;
}
p {
margin: 200px 10px;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="container">
<header><h2>Hi</h2></header>
<p class="trigger" data-title="section1">
trigger1
</p>
<p class="trigger" data-title="section2">
trigger2
</p>
<p class="trigger" data-title="section3">
trigger3
</p>
</div>
As you scroll down the page, each trigger hits the top of the page, and the text in the header will change to the the value of the latest trigger's data-title. You could position these triggers appropriately above each of your website's sections, so that, no matter what size the screen, the header should update at the right time. Here's a codepen.
EDIT
Try this JS instead for maximum compatibility (no es6 involved).
function updateHeader() {
var scrollTop = $(window).scrollTop(),
triggerTitle = "Hi";
$('.trigger').each(function(i, el) {
var topPos = $(el).offset().top,
distance = topPos - scrollTop;
if (distance < 0)
triggerTitle = $(el).data('title');
});
$('header h2').text(triggerTitle);
}
$(window).scroll(updateHeader);
$(window).on('touchmove', updateHeader);