How do I know when I've stopped scrolling?
JavascriptScrollDom EventsJavascript Problem Overview
How do I know when I've stopped scrolling using Javascript?
Javascript Solutions
Solution 1 - Javascript
You can add an event handler for the scroll event and start a timeout. Something like:
var timer = null;
window.addEventListener('scroll', function() {
if(timer !== null) {
clearTimeout(timer);
}
timer = setTimeout(function() {
// do something
}, 150);
}, false);
This will start a timeout and wait 150ms. If a new scroll event occurred in the meantime, the timer is aborted and a new one is created. If not, the function will be executed. You probably have to adjust the timing.
Also note that IE uses a different way to attach event listeners, this should give a good introduction: quirksmode - Advanced event registration models
Solution 2 - Javascript
There isn't a "Stopped Scrolling" event. If you want to do something after the user has finished scrolling, you can set a timer in the "OnScroll" event. If you get another "OnScroll" event fired then reset the timer. When the timer finally does fire, then you can assume the scrolling has stopped. I would think 500 milliseconds would be a good duration to start with.
Here's some sample code that works in IE and Chrome:
<html>
<body onscroll="bodyScroll();">
<script language="javascript">
var scrollTimer = -1;
function bodyScroll() {
document.body.style.backgroundColor = "white";
if (scrollTimer != -1)
clearTimeout(scrollTimer);
scrollTimer = window.setTimeout("scrollFinished()", 500);
}
function scrollFinished() {
document.body.style.backgroundColor = "red";
}
</script>
<div style="height:2000px;">
Scroll the page down. The page will turn red when the scrolling has finished.
</div>
</body>
</html>
Solution 3 - Javascript
Here's a more modern, Promise-based solution I found on a repo called scroll-into-view-if-needed
Instead of using addEventListener on the scroll event it uses requestAnimationFrame to watch for frames with no movement and resolves when there have been 20 frames without movement.
function waitForScrollEnd () {
let last_changed_frame = 0
let last_x = window.scrollX
let last_y = window.scrollY
return new Promise( resolve => {
function tick(frames) {
// We requestAnimationFrame either for 500 frames or until 20 frames with
// no change have been observed.
if (frames >= 500 || frames - last_changed_frame > 20) {
resolve()
} else {
if (window.scrollX != last_x || window.scrollY != last_y) {
last_changed_frame = frames
last_x = window.scrollX
last_y = window.scrollY
}
requestAnimationFrame(tick.bind(null, frames + 1))
}
}
tick(0)
})
}
With async/await and then
await waitForScrollEnd()
waitForScrollEnd().then(() => { /* Do things */ })
Solution 4 - Javascript
(function( $ ) {
$(function() {
var $output = $( "#output" ),
scrolling = "<span id='scrolling'>Scrolling</span>",
stopped = "<span id='stopped'>Stopped</span>";
$( window ).scroll(function() {
$output.html( scrolling );
clearTimeout( $.data( this, "scrollCheck" ) );
$.data( this, "scrollCheck", setTimeout(function() {
$output.html( stopped );
}, 250) );
});
});
})( jQuery );
=======>>>> Working Example here
Solution 5 - Javascript
I did something like this:
var scrollEvents = (function(document, $){
var d = {
scrolling: false,
scrollDirection : 'none',
scrollTop: 0,
eventRegister: {
scroll: [],
scrollToTop: [],
scrollToBottom: [],
scrollStarted: [],
scrollStopped: [],
scrollToTopStarted: [],
scrollToBottomStarted: []
},
getScrollTop: function(){
return d.scrollTop;
},
setScrollTop: function(y){
d.scrollTop = y;
},
isScrolling: function(){
return d.scrolling;
},
setScrolling: function(bool){
var oldVal = d.isScrolling();
d.scrolling = bool;
if(bool){
d.executeCallbacks('scroll');
if(oldVal !== bool){
d.executeCallbacks('scrollStarted');
}
}else{
d.executeCallbacks('scrollStopped');
}
},
getScrollDirection : function(){
return d.scrollDirection;
},
setScrollDirection : function(direction){
var oldDirection = d.getScrollDirection();
d.scrollDirection = direction;
if(direction === 'UP'){
d.executeCallbacks('scrollToTop');
if(direction !== oldDirection){
d.executeCallbacks('scrollToTopStarted');
}
}else if(direction === 'DOWN'){
d.executeCallbacks('scrollToBottom');
if(direction !== oldDirection){
d.executeCallbacks('scrollToBottomStarted');
}
}
},
init : function(){
d.setScrollTop($(document).scrollTop());
var timer = null;
$(window).scroll(function(){
d.setScrolling(true);
var x = d.getScrollTop();
setTimeout(function(){
var y = $(document).scrollTop();
d.setScrollTop(y);
if(x > y){
d.setScrollDirection('UP');
}else{
d.setScrollDirection('DOWN');
}
}, 100);
if(timer !== 'undefined' && timer !== null){
clearTimeout(timer);
}
timer = setTimeout(function(){
d.setScrolling(false);
d.setScrollDirection('NONE');
}, 200);
});
},
registerEvents : function(eventName, callback){
if(typeof eventName !== 'undefined' && typeof callback === 'function' && typeof d.eventRegister[eventName] !== 'undefined'){
d.eventRegister[eventName].push(callback);
}
},
executeCallbacks: function(eventName){
var callabacks = d.eventRegister[eventName];
for(var k in callabacks){
if(callabacks.hasOwnProperty(k)){
callabacks[k](d.getScrollTop());
}
}
}
};
return d;
})(document, $);
the code is available here: documentScrollEvents
Solution 6 - Javascript
Minor update in your answer. Use mouseover and out function.
$(document).ready(function() {
function ticker() {
$('#ticker li:first').slideUp(function() {
$(this).appendTo($('#ticker')).slideDown();
});
}
var ticke= setInterval(function(){
ticker();
}, 3000);
$('#ticker li').mouseover(function() {
clearInterval(ticke);
}).mouseout(function() {
ticke= setInterval(function(){ ticker(); }, 3000);
});
});
Solution 7 - Javascript
I was trying too add a display:block property for social icons that was previously hidden on scroll event and then again hide after 2seconds. But
I too had a same problem as my code for timeout after first scroll would start automatically and did not had reset timeout idea. As it didn't had proper reset function.But after I saw David's idea on this question I was able to reset timeout even if someone again scrolled before actually completing previous timeout.
-
problem code shown below before solving
$(window).scroll(function(){ setTimeout(function(){ $('.fixed-class').slideUp('slow'); },2000); });
-
edited and working code with reset timer if next scroll occurs before 2s
var timer=null; $(window).scroll(function(){ $('.fixed-class').css("display", "block"); if(timer !== null) { clearTimeout(timer);
} timer=setTimeout(function(){ $('.fixed-class').slideUp('slow'); },2000);
});
My working code will trigger a hidden division of class named 'fixed-class' to show in block on every scroll. From start of latest scroll the timer will count 2 sec and then again change the display from block to hidden.
Solution 8 - Javascript
For more precision you can also check the scroll position:
function onScrollEndOnce(callback, target = null) {
let timeout
let targetTop
const startPosition = Math.ceil(document.documentElement.scrollTop)
if (target) {
targetTop = Math.ceil(target.getBoundingClientRect().top + document.documentElement.scrollTop)
}
function finish(removeEventListener = true) {
if (removeEventListener) {
window.removeEventListener('scroll', onScroll)
}
callback()
}
function isScrollReached() {
const currentPosition = Math.ceil(document.documentElement.scrollTop)
if (targetTop == null) {
return false
} else if (targetTop >= startPosition) {
return currentPosition >= targetTop
} else {
return currentPosition <= targetTop
}
}
function onScroll() {
if (timeout) {
clearTimeout(timeout)
}
if (isScrollReached()) {
finish()
} else {
timeout = setTimeout(finish, 500)
}
}
if (isScrollReached()) {
finish(false)
} else {
window.addEventListener('scroll', onScroll)
}
}
Usage example:
const target = document.querySelector('#some-element')
onScrollEndOnce(() => console.log('scroll end'), target)
window.scrollTo({
top: Math.ceil(target.getBoundingClientRect().top + document.documentElement.scrollTop),
behavior: 'smooth',
})