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 currently developing a plugin for existing websites.
Its purpose is to display a sidebar with my content. To that end, the website owner creates an empty div, references my javascript file and calls my code with the ID of the empty div.
My plugin is then creating an iFrame in that empty div and loads its content. It also is responsible for styling the provided div so that it actually is a sidebar: It changes the width and height of that div and attaches it to the right edge of the screen.
So, all of that is basically working - loading my iFrame and styling the div.
The problem is that I am not satisfied with the result.
I have tried two different styles for the div:
Approach 1: float right
I used this CSS:
float: right;
height: 100%;
width: 100px;
The problem with this is that it doesn't change the total width of the rest of the page. In other words, elements on the website with a width: 100% will be shown below my sidebar.
https://jsfiddle.net/DHilgarth/mmzefm14/
Approach 2: Absolute positioning
I used this CSS:
position: absolute;
top: 0;
right: 0;
height: 100%;
width: 100px;
This approach has the problem that my sidebar now simply overlaps the controls from the website.
https://jsfiddle.net/DHilgarth/34hmnw9h/1/
Is there a way to achieve what I want? A sidebar that basically reduces the available size of the body for all elements, except mine?
I have now chosen to actually do exactly what I asked for: I reduce the available width of the body tag.
This is not trivial because of box-sizing, padding, margin, border etc and I am sure I have missed a lot of edge cases but for now, the following logic is working for me:
If box-sizing is border-box: set the right padding of the body element to the width of my sidebar.
Otherwise, set the width of the body element to the width of the body element minus the width of the sidebar. On resize of the window, the width of the body has to be adjusted accordingly.
Code:
function initSidebar() {
loadSidebar("sidebar");
}
// This code would be loaded from a javascript file I provide
function css(element, property) {
return window.getComputedStyle(element, null).getPropertyValue(property);
}
function getSidebarWidth(sidebarElement) {
var boundingRect = sidebarElement.getBoundingClientRect();
return boundingRect.right - boundingRect.left;
}
function styleBorderBoxBody(bodyElement, sidebarElement) {
bodyElement.style.paddingRight = getSidebarWidth(sidebarElement) + "px";
}
function resizeBody(bodyElement, previousWindowWidth, previousBodyWidth) {
var currentWindowWidth = window.innerWidth;
var newBodyWidth = previousBodyWidth - previousWindowWidth + currentWindowWidth;
bodyElement.style.width = newBodyWidth + "px";
return {currentWindowWidth, newBodyWidth};
}
function styleBody(bodyElement, sidebarElement) {
var boxSizing = css(bodyElement, "box-sizing");
if(boxSizing == "content-box" || !boxSizing || boxSizing == "") {
var sidebarWidth = getSidebarWidth(sidebarElement);
var width = bodyElement.clientWidth - sidebarWidth;
bodyElement.style.width = width + "px";
sidebarElement.style.right = (-sidebarWidth) + "px";
var windowWidth = window.innerWidth;
window.addEventListener("resize", function(e) {
var newWidths = resizeBody(bodyElement, windowWidth, width);
width = newWidths.newBodyWidth;
windowWidth = newWidths.currentWindowWidth;
});
} else if(boxSizing == "border-box") {
styleBorderBoxBody(bodyElement, sidebarElement);
window.addEventListener("resize", function(e) { styleBorderBoxBody(bodyElement, sidebarElement); });
}
}
function loadSidebar(sidebarId) {
var sidebarElement = document.getElementById(sidebarId);
sidebarElement.className = "sidebar";
var bodyElement = document.getElementsByTagName("body")[0];
styleBody(bodyElement, sidebarElement);
}
// end: my code
initSidebar();
* {
margin: 0;
padding: 0;
}
html {
}
*,
*:before,
*:after {
box-sizing: inherit;
}
body {
font: 14px/1.1 Helvetica, Sans-Serif;
position: absolute;
left: 0;
right: 0;
top: 0;
bottom: 0;
height: 100%;
}
#editor {
width: 100%;
height: 500px;
}
/* this class would be loaded from a CSS file I provide */
.sidebar {
border-color: green;
border-style: solid;
position: fixed;
top: 0;
right: 0;
bottom: 0;
width: 100px;
}
<div id="sidebar"></div>
<h1>Some UI from the existing website</h1>
<textarea id="editor">The text area</textarea>
How can I make my navbar stick after scrolling to a certain point on page? I don't want it to stick immediately after scrolling past it, but rather once I reach another div on the page.
Try this:
window.onscroll = function() {
var scrollTop = (window.pageYOffset !== undefined) ? window.pageYOffset : (document.documentElement || document.body.parentNode || document.body).scrollTop;
if (scrollTop >= document.getElementById("d").offsetTop) {
document.getElementById("nav").style.position = "fixed";
document.getElementById("d").style.marginTop = "50px";
document.getElementById("nav").style.marginTop = "-50px";
} else {
document.getElementById("nav").style.position = "static";
document.getElementById("d").style.marginTop = "0px";
document.getElementById("nav").style.marginTop = "0px";
}
}
nav {
width: 100%;
height: 50px;
background: red;
z-index: 100;
}
body {
margin: 0;
min-height: 1000px
}
#d {
position: relative;
top: 100px;
width: 100%;
height: 50px;
background: yellow;
}
<body>
<nav id="nav"></nav>
<div id="d"></div>
</body>
When you scroll to the yellow div, the red navbar sticks to the top of the viewport and stays there until you scroll up