I am creating a chat using Ajax requests and I'm trying to get messages div to scroll to the bottom without much luck.
I am wrapping everything in this div:
#scroll {
height:400px;
overflow:scroll;
}
Is there a way to keep it scrolled to the bottom by default using JS?
Is there a way to keep it scrolled to the bottom after an ajax request?
Here's what I use on my site:
var objDiv = document.getElementById("your_div");
objDiv.scrollTop = objDiv.scrollHeight;
This is much easier if you're using jQuery scrollTop:
$("#mydiv").scrollTop($("#mydiv")[0].scrollHeight);
Try the code below:
const scrollToBottom = (id) => {
const element = document.getElementById(id);
element.scrollTop = element.scrollHeight;
}
You can also use Jquery to make the scroll smooth:
const scrollSmoothlyToBottom = (id) => {
const element = $(`#${id}`);
element.animate({
scrollTop: element.prop("scrollHeight")
}, 500);
}
Here is the demo
Here's how it works:
Ref: scrollTop, scrollHeight, clientHeight
using jQuery animate:
$('#DebugContainer').stop().animate({
scrollTop: $('#DebugContainer')[0].scrollHeight
}, 800);
Newer method that works on all current browsers:
this.scrollIntoView(false);
var mydiv = $("#scroll");
mydiv.scrollTop(mydiv.prop("scrollHeight"));
Works from jQuery 1.6
https://api.jquery.com/scrollTop/
http://api.jquery.com/prop/
alternative solution
function scrollToBottom(element) {
element.scroll({ top: element.scrollHeight, behavior: 'smooth' });
}
smooth scroll with Javascript:
document.getElementById('messages').scrollIntoView({ behavior: 'smooth', block: 'end' });
If you don't want to rely on scrollHeight, the following code helps:
$('#scroll').scrollTop(1000000);
Java Script:
document.getElementById('messages').scrollIntoView(false);
Scrolls to the last line of the content present.
My Scenario: I had an list of string, in which I had to append a string given by a user and scroll to the end of the list automatically. I had fixed height of the display of the list, after which it should overflow.
I tried #Jeremy Ruten's answer, it worked, but it was scrolling to the (n-1)th element. If anybody is facing this type of issue, you can use setTimeOut() method workaround. You need to modify the code to below:
setTimeout(() => {
var objDiv = document.getElementById('div_id');
objDiv.scrollTop = objDiv.scrollHeight
}, 0)
Here is the StcakBlitz link I have created which shows the problem and its solution : https://stackblitz.com/edit/angular-ivy-x9esw8
If your project targets modern browsers, you can now use CSS Scroll Snap to control the scrolling behavior, such as keeping any dynamically generated element at the bottom.
.wrapper > div {
background-color: white;
border-radius: 5px;
padding: 5px 10px;
text-align: center;
font-family: system-ui, sans-serif;
}
.wrapper {
display: flex;
padding: 5px;
background-color: #ccc;
border-radius: 5px;
flex-direction: column;
gap: 5px;
margin: 10px;
max-height: 150px;
/* Control snap from here */
overflow-y: auto;
overscroll-behavior-y: contain;
scroll-snap-type: y mandatory;
}
.wrapper > div:last-child {
scroll-snap-align: start;
}
<div class="wrapper">
<div>01</div>
<div>02</div>
<div>03</div>
<div>04</div>
<div>05</div>
<div>06</div>
<div>07</div>
<div>08</div>
<div>09</div>
<div>10</div>
</div>
You can use the HTML DOM scrollIntoView Method like this:
var element = document.getElementById("scroll");
element.scrollIntoView();
Javascript or jquery:
var scroll = document.getElementById('messages');
scroll.scrollTop = scroll.scrollHeight;
scroll.animate({scrollTop: scroll.scrollHeight});
Css:
.messages
{
height: 100%;
overflow: auto;
}
Using jQuery, scrollTop is used to set the vertical position of scollbar for any given element. there is also a nice jquery scrollTo plugin used to scroll with animation and different options (demos)
var myDiv = $("#div_id").get(0);
myDiv.scrollTop = myDiv.scrollHeight;
if you want to use jQuery's animate method to add animation while scrolling down, check the following snippet:
var myDiv = $("#div_id").get(0);
myDiv.animate({
scrollTop: myDiv.scrollHeight
}, 500);
I have encountered the same problem, but with an additional constraint: I had no control over the code that appended new elements to the scroll container. None of the examples I found here allowed me to do just that. Here is the solution I ended up with .
It uses Mutation Observers (https://developer.mozilla.org/en-US/docs/Web/API/MutationObserver) which makes it usable only on modern browsers (though polyfills exist)
So basically the code does just that :
var scrollContainer = document.getElementById("myId");
// Define the Mutation Observer
var observer = new MutationObserver(function(mutations) {
// Compute sum of the heights of added Nodes
var newNodesHeight = mutations.reduce(function(sum, mutation) {
return sum + [].slice.call(mutation.addedNodes)
.map(function (node) { return node.scrollHeight || 0; })
.reduce(function(sum, height) {return sum + height});
}, 0);
// Scroll to bottom if it was already scrolled to bottom
if (scrollContainer.clientHeight + scrollContainer.scrollTop + newNodesHeight + 10 >= scrollContainer.scrollHeight) {
scrollContainer.scrollTop = scrollContainer.scrollHeight;
}
});
// Observe the DOM Element
observer.observe(scrollContainer, {childList: true});
I made a fiddle to demonstrate the concept :
https://jsfiddle.net/j17r4bnk/
Found this really helpful, thank you.
For the Angular 1.X folks out there:
angular.module('myApp').controller('myController', ['$scope', '$document',
function($scope, $document) {
var overflowScrollElement = $document[0].getElementById('your_overflow_scroll_div');
overflowScrollElement[0].scrollTop = overflowScrollElement[0].scrollHeight;
}
]);
Just because the wrapping in jQuery elements versus HTML DOM elements gets a little confusing with angular.
Also for a chat application, I found making this assignment after your chats were loaded to be useful, you also might need to slap on short timeout as well.
Like you, I'm building a chat app and want the most recent message to scroll into view. This ultimately worked well for me:
//get the div that contains all the messages
let div = document.getElementById('message-container');
//make the last element (a message) to scroll into view, smoothly!
div.lastElementChild.scrollIntoView({ behavior: 'smooth' });
small addendum: scrolls only, if last line is already visible. if scrolled a tiny bit, leaves the content where it is (attention: not tested with different font sizes. this may need some adjustments inside ">= comparison"):
var objDiv = document.getElementById(id);
var doScroll=objDiv.scrollTop>=(objDiv.scrollHeight-objDiv.clientHeight);
// add new content to div
$('#' + id ).append("new line at end<br>"); // this is jquery!
// doScroll is true, if we the bottom line is already visible
if( doScroll) objDiv.scrollTop = objDiv.scrollHeight;
Just as a bonus snippet. I'm using angular and was trying to scroll a message thread to the bottom when a user selected different conversations with users. In order to make sure that the scroll works after the new data had been loaded into the div with the ng-repeat for messages, just wrap the scroll snippet in a timeout.
$timeout(function(){
var messageThread = document.getElementById('message-thread-div-id');
messageThread.scrollTop = messageThread.scrollHeight;
},0)
That will make sure that the scroll event is fired after the data has been inserted into the DOM.
This will let you scroll all the way down regards the document height
$('html, body').animate({scrollTop:$(document).height()}, 1000);
You can also, using jQuery, attach an animation to html,body of the document via:
$("html,body").animate({scrollTop:$("#div-id")[0].offsetTop}, 1000);
which will result in a smooth scroll to the top of the div with id "div-id".
Scroll to the last element inside the div:
myDiv.scrollTop = myDiv.lastChild.offsetTop
You can use the Element.scrollTo() method.
It can be animated using the built-in browser/OS animation, so it's super smooth.
function scrollToBottom() {
const scrollContainer = document.getElementById('container');
scrollContainer.scrollTo({
top: scrollContainer.scrollHeight,
left: 0,
behavior: 'smooth'
});
}
// initialize dummy content
const scrollContainer = document.getElementById('container');
const numCards = 100;
let contentInnerHtml = '';
for (let i=0; i<numCards; i++) {
contentInnerHtml += `<div class="card mb-2"><div class="card-body">Card ${i + 1}</div></div>`;
}
scrollContainer.innerHTML = contentInnerHtml;
.overflow-y-scroll {
overflow-y: scroll;
}
<link href="https://cdn.jsdelivr.net/npm/bootstrap#4.5.3/dist/css/bootstrap.min.css" rel="stylesheet"/>
<div class="d-flex flex-column vh-100">
<div id="container" class="overflow-y-scroll flex-grow-1"></div>
<div>
<button class="btn btn-primary" onclick="scrollToBottom()">Scroll to bottom</button>
</div>
</div>
Css only:
.scroll-container {
overflow-anchor: none;
}
Makes it so the scroll bar doesn't stay anchored to the top when a child element is added. For example, when new message is added at the bottom of chat, scroll chat to new message.
Why not use simple CSS to do this?
The trick is to use display: flex; and flex-direction: column-reverse;
Here is a working example. https://codepen.io/jimbol/pen/YVJzBg
A very simple method to this is to set the scroll to to the height of the div.
var myDiv = document.getElementById("myDiv");
window.scrollTo(0, myDiv.innerHeight);
On my Angular 6 application I just did this:
postMessage() {
// post functions here
let history = document.getElementById('history')
let interval
interval = setInterval(function() {
history.scrollTop = history.scrollHeight
clearInterval(interval)
}, 1)
}
The clearInterval(interval) function will stop the timer to allow manual scroll top / bottom.
I know this is an old question, but none of these solutions worked out for me. I ended up using offset().top to get the desired results. Here's what I used to gently scroll the screen down to the last message in my chat application:
$("#html, body").stop().animate({
scrollTop: $("#last-message").offset().top
}, 2000);
I hope this helps someone else.
I use the difference between the Y coordinate of the first item div and the Y coordinate of the selected item div. Here is the JavaScript/JQuery code and the html:
function scrollTo(event){
// In my proof of concept, I had a few <button>s with value
// attributes containing strings with id selector expressions
// like "#item1".
let selectItem = $($(event.target).attr('value'));
let selectedDivTop = selectItem.offset().top;
let scrollingDiv = selectItem.parent();
let firstItem = scrollingDiv.children('div').first();
let firstItemTop = firstItem.offset().top;
let newScrollValue = selectedDivTop - firstItemTop;
scrollingDiv.scrollTop(newScrollValue);
}
<div id="scrolling" style="height: 2rem; overflow-y: scroll">
<div id="item1">One</div>
<div id="item2">Two</div>
<div id="item3">Three</div>
<div id="item4">Four</div>
<div id="item5">Five</div>
</div>
On my page there is ajax action, which loads div, that contain image on left and text on right.
The problem: first of all text loads, and on the left (it aligned left), then image loads, text shifts on right, and that looks really not smooth.
I tried something like :
$('div#to_load').ready(function() {
$('div#to_load').fadeIn();
});
but that doesn't help.
What can I do?
Update
I think you have to try this trick found here :
$("<img />", { src:"thelinkofyourimage"}).appendTo("div#to_load").fadeOut(0).fadeIn(1000);
Have a look to this fiddle : http://jsfiddle.net/qYHCn/.
You could track when all the images have loaded like so
var element = $('div#to_load');
var images = element.find('img');
var count = images.length;
for( var i = 0; i < count; i++) {
$(images[i]).load(function(){
count--;
if( count === 0 ){
element.fadeIn();
}
});
}
You could smoothly animate it in with jQuery (handy anyway when you are doing your ajax requests with jQuery):
jQuery
$("body").prepend('<img src="http://placehold.it/150x150" alt="img">');
$("img").animate({
opacity: 1,
left: 0
}, 700);
CSS
img {
float: left;
margin-right: 0.8em ;
left: -300px;
position: relative;
}
Fiddle.
Try to load image and text separately, not at once.
And for the shifting problem put image inside another div and define the size when it loads. Then text can't come to image space since we already giving space for image div.
sample code
$('#ImageID')
.load(
function(){
//Do stuff once the image specified above is loaded
$('#textId').html('your text');
}
);
If you don't want content to shift, you must declare the size the image will take up so that the required space is already accounted for when the browser does it's render.
Make sure you declare the size of the image, or the size of the container before you load
<div id="to_load">
<img src="...." height="400" width="400" />
</div>
or
<div id="to_load" style="height:400px;width:400px;overflow:hidden">
..dynamic content
</div>
Declaring image size either on the img element or in your stylesheet is a best practice recommendation anyways
Reflows & Repaint
Maybe you'd like something like this
#to_load {
width: 523px;
height: 192px;
}
#to_load img {
display: none;
}
setTimeout(function() {
$("<img />", { src:"http://ejohn.org/apps/workshop/adv-talk/jquery_logo.png"})
.on('load', function(){
$(this).appendTo("#to_load").fadeIn(500);
});
},1000);
http://jsfiddle.net/AWntU/
I'm new to javascript and I have this jQuery that replaces one image when the screen size is shrunk down to 480px. The thing is that I'd like to add a lot more images to do the same thing.
The only solution i got to work was to paste the code over and over again and replace the image values with new ones.
So how can I create several ifs and elses in the same script?
$(document).ready(function() {
function imageresize() {
var contentwidth = $('body').width();
if ((contentwidth) < '480'){
$('.spelguide').attr('src','bilder/480/spelguide.jpg');
} else {
$('.spelguide').attr('src','bilder/spelguide.jpg');
}
}
imageresize();//Triggers when document first loads
$(window).bind("resize", function(){//Adjusts image when browser resized
imageresize();
});
});
The usual pattern for chaining multiple if-else-ifs is doing something like
if (some_condition) {
// do stuff
} else if (some_other_condition) {
// do other stuff
} else if (another_condition) {
// do another thing
} else {
//default case
}
This is not just for Javascript. In most other programming languages with an if statement it will look similar to this.
You want If..Else If..Else ? If so http://www.w3schools.com/js/js_if_else.asp gives an example.
Here's what I would do (assuming I understand your question correctly). The short answer, I would say is to: Use a "for" loop.
First, I would give each image a UNIQUE id (instead of a class):
<img id="example_img_id1" src="..." />
In my JavaScript, I would create a JSON object that has a (key : value) pair storing the (id : image_name) of each image (see below).
Then, I would use a for/in loop that iterates over a JSON object.
In your JSON object, add each of your unique img ids as the key and the name of the image as the value. Do this for all of the images that you have.
// get the width of your body
var contentwidth = $('body').width();
// key: value -----> '#img_id': 'src'
var imgs = {
'#example_img_id1' : 'imgname1.jpg',
'#example_img_id2' : 'imgname2.jpg',
'#example_img_id3' : 'imgname3.jpg',
// ...
'#example_img_idn' : 'imgname4.jpg'
};
// iterate over each image and create its new src
for(var img in imgs) {
// set the value of your src string
var src = '';
if(contentwidth < 480) { // if the screen size is less than 480
src = '/bilder/480/' + imgs.img; // add the "/480/" directory
} else { // anything 480 and larger
src = '/bilder/' + imgs.img; // don't add "/480/"
}
// for every image in your JSON object (imgs),
// it will create a jQuery object - $(img) - and
// update its src attribute based on the screen width.
$(img).attr('src', src);
}
There's more than one way to skin a cat, and by no means is this the "best" or "most efficient" approach. Hopefully it at least points you in the right direction. Does this all make sense?
Forget doing all that with javascript, let CSS do most of the work.
Just set a determining class on the body with javascript.
Javascript:
$(window).bind("resize", function(){
var body = $('body');
var bodyWidth = body.width();
body.toggleClass('size-480', bodyWidth < 480);
});
HTML:
<img src="transparant.gif" class="img-spelguide" />
CSS:
img.img-spelguide {
width: 400px; /*adjust accordingly*/
height: 400px; /*adjust accordingly*/
background: url(bilder/spelguide.jpg) 50% 50% no-repeat;
}
.size-480 img.img-spelguide {
width: 200px; /*adjust accordingly*/
height: 200px; /*adjust accordingly*/
background: url(bilder/480/spelguide.jpg) 50% 50% no-repeat;
}
You could still replace a lot of images using purely javascript, but CSS is better suited.
Note. if you can use #media-queries, please do so, thats the best option, however if you need to support legacy browsers, media-queries are obviously out =(
Lets throw in the javascript solution as well for good measure.
HTML:
<img src="bilder/spelguide.jpg" data-small="bilder/480/spelguide.jpg" />
JAVASCRIPT:
$(window).bind("resize", function(){
var body = $('body');
var useSmall = body.width() < 480;
$('img[data-small]').each(function(){
var img = $(this);
var big = img.data( 'big') || img.attr('src');
var small = img.data('small');
// make sure we have the original (big) src stored.
img.data( 'big', big );
img.attr( 'src', useSmall ? small : big );
});
});
Still some room for optimisation.
I am trying to add a scroll event which will change the background of a div which also acts as the window background (it has 100% width and height). This is as far as I get. I am not so good at jquery. I have seen tutorials with click event listeners. but applying the same concept , like, returning scroll event as false, gets me nowhere. also I saw a tutorial on SO where the person suggest use of array. but I get pretty confused using arrays (mostly due to syntax).
I know about plugins like waypoints.js and skrollr.js which can be used but I need to change around 50-60 (for the illusion of a video being played when scrolled) ... but it wont be feasible.
here is the code im using:-
*
{
border: 2px solid black;
}
#frame
{
background: url('1.jpg') no-repeat;
height: 1000px;
width: 100%;
}
</style>
<script>
$(function(){
for ( i=0; i = $.scrolltop; i++)
{
$("#frame").attr('src', ''+i+'.jpg');
}
});
</script>
<body>
<div id="frame"></div>
</body>
Inside your for loop, you are setting the src attribute of #frame but it is a div not an img.
So, instead of this:
$("#frame").attr('src', ''+i+'.jpg');
Try this:
$("#frame").css('background-image', 'url(' + i + '.jpg)');
To bind a scroll event to a target element with jQuery:
$('#target').scroll(function() {
//do stuff here
});
To bind a scroll event to the window with jQuery:
$(window).scroll(function () {
//do stuff here
});
Here is the documentation for jQuery .scroll().
UPDATE:
If I understand right, here is a working demo on jsFiddle of what you want to achieve.
CSS:
html, body {
min-height: 1200px; /* for testing the scroll bar */
}
div#frame {
display: block;
position: fixed; /* Set this to fixed to lock that element on the position */
width: 300px;
height: 300px;
z-index: -1; /* Keep the bg frame at the bottom of other elements. */
}
Javascript:
$(document).ready(function() {
switchImage();
});
$(window).scroll(function () {
switchImage();
});
//using images from dummyimages.com for demonstration (300px by 300px)
var images = ["http://dummyimage.com/300x300/000000/fff",
"http://dummyimage.com/300x300/ffcc00/000",
"http://dummyimage.com/300x300/ff0000/000",
"http://dummyimage.com/300x300/ff00cc/000",
"http://dummyimage.com/300x300/ccff00/000"
];
//Gets a valid index from the image array using the scroll-y value as a factor.
function switchImage()
{
var sTop = $(window).scrollTop();
var index = sTop > 0 ? $(document).height() / sTop : 0;
index = Math.round(index) % images.length;
//console.log(index);
$("#frame").css('background-image', 'url(' + images[index] + ')');
}
HTML:
<div id="frame"></div>
Further Suggestions:
I suggest you change the background-image of the body, instead of the div. But, if you have to use a div for this; then you better add a resize event-istener to the window and set/update the height of that div with every resize. The reason is; height:100% does not work as expected in any browser.
I've done this before myself and if I were you I wouldn't use the image as a background, instead use a normal "img" tag prepend it to the top of your page use some css to ensure it stays in the back under all of the other elements. This way you could manipulate the size of the image to fit screen width better. I ran into a lot of issues trying to get the background to size correctly.
Html markup:
<body>
<img src="1.jpg" id="img" />
</body>
Script code:
$(function(){
var topPage = 0, count = 0;
$(window).scroll( function() {
topPage = $(document).scrollTop();
if(topPage > 200) {
// function goes here
$('img').attr('src', ++count +'.jpg');
}
});
});
I'm not totally sure if this is what you're trying to do but basically, when the window is scrolled, you assign the value of the distance to the top of the page, then you can run an if statement to see if you are a certain point. After that just simply change run the function you would like to run.
If you want to supply a range you want the image to change from do something like this, so what will happen is this will allow you to run a function only between the specificied range between 200 and 400 which is the distance from the top of the page.
$(function(){
var topPage = 0, count = 0;
$(window).scroll( function() {
topPage = $(document).scrollTop();
if(topPage > 200 && topPage < 400) {
// function goes here
$('#img').attr('src', ++count +'.jpg');
}
});
});
I have some simple code to replace an image src. It is working correctly but everytime the image is updated, the browser skips right back to the top of the page.
I have several image tags in my page. All of which hidden, except for the first one. The script just iterates through them and uses the src attribute to update the first image.
Here is the code I am using:
var j = jQuery.noConflict();
var count = 1;
var img;
function update_main_image()
{
count++;
if (j('#main_image_picture_'+count).length > 0)
{
img = j('#main_image_picture_'+count).attr('src');
}
else
{
count = 1;
img = j('#main_image_picture_'+count).attr('src');
}
j(".main_image_picture_auto").fadeOut(1500, function() {
j(this).fadeIn();
j(this).attr("src", img);
});
}
j(document).ready(function()
{
setInterval(update_main_image, 6000);
});
Any ideas what might be causing it?
Any advice appreciated.
Thanks.
Try to add DIV around your IMG.main_image_picture_auto with width and height style properties setted to maximum posible image size, for example:
<div style='width:400px; height:400px; border: 0px; background: transparent; '>
<img class='main_image_picture_auto' src=''/>
</div>
<!-- Where width:400px and height:400px is maximum allowed image size -->
And I think, that is better to use setTimeout instead of setInterval
function update_main_image() {
// ....
setTimeout(update_main_image, 6000);
}
j(document).ready(function() {
setTimeout(update_main_image, 6000);
});
http://jsfiddle.net/UBEWS/