Develop Reference

Too many scroll events for smooth scrolling

Hello there I've been trying to find a fix for the many scroll events firing on one scroll. This is the only thing close to working for me so far. I want to smoothscroll between two divs (#boxes and #header) I want to use the scroll bar to trigger this smooth scroll and not a button. Any suggestions on how to only take one scroll event? I also used solutions based from prev stackoverflow questions. I used my own locator instead of offsets because thats also unreliable
$(window).scroll(function () {
if (timer) {
window.clearTimeout(timer);
}
timer = window.setTimeout(function () {
if (locator == 0) {
id = $("#boxes");
locator = 1;
} else if (locator = 1) {
id = $("#header");
locator = 0;
}
// target element
var $id = $(id);
if ($id.length === 0) {
return;
}
// top position relative to the document
var pos = $id.offset().top;
// animated top scrolling
$('html, body').animate({scrollTop: pos}, 1500, function () {
$('html, body').clearQueue();
$('html, body').stop();
});
}, 2);
});

So, to be clear, you want any minor scroll event to scroll between one item and the other? Note that when a user scrolls, there is a "momentum" that the browser implements, and you'll be battling with that.
Regardless: You don't need to wrap this in a setTimeout. Right now, your javascript is creating a new setTimeout function that is being fired every 2ms. Scroll events occur with every pixel of movement in the scroll, so if you scroll 100px, you're going to be firing 100 times every 2ms. (That's 50,000 times).
Instead, have a a variable (isScrolling) track the state, so, if you're in the middle of scrolling, the function won't fire.
var isScrolling = false;
var locator = 0;
$(window).scroll(function () {
if (isScrolling) return false;
if (locator == 0) {
id = $("#boxes");
locator = 1;
} else if (locator = 1) {
id = $("#header");
locator = 0;
}
// target element
var $id = $(id);
if ($id.length === 0) {
return;
}
// top position relative to the document
var pos = $id.offset().top;
// animated top scrolling
isScrolling = true;
$('html, body').animate({scrollTop: pos}, 1500, function () {
$('html, body').clearQueue();
$('html, body').stop();
isScrolling = false;
});
});
Here's a JSbin: http://jsbin.com/jugefup/edit?html,css,js,output

Slide div on and off the page on scroll without interrupting the animation when the user continues to scroll

I am trying to smoothly slide a div on and off the page (left to right) using jQuery only. I have accomplished the task, however if you continue to scroll up or down while the animation is still going, it will interrupt it in the middle of the action causing it to hesitate. I've run into this issue before and could never figure it out without using a plugin of some sort.
I know how to accomplish this with CSS transitions, jQuery UI, greensock, etc., but I am curious if there is a way to prevent that interruption with jQuery only. I am open to a pure JavaScript solution (no jQuery) as well if there is one.
My code:
var amountScrolled = 50;
$(window).scroll(function() {
if ($(window).scrollTop() > amountScrolled) {
$('#slide').stop().animate({marginLeft:"0px"}, 500);
} else {
$('#slide').stop().animate({marginLeft: "-400px"}, 500);
}
});
Example: https://jsfiddle.net/Hysteresis/hg9cvxop/6/

This works: JSFIDDLE link
It's all about the Callback Functions!
var amountScrolled = 50;
var loopRunning = 0;
$(window).scroll(function() {
if ($(window).scrollTop() > amountScrolled){
if(loopRunning === 0){
animateSlide("0px",500);
}
} else {
if(loopRunning === 0){
animateSlide("-400px",500);
}
}
});
function animateSlide(px, time){
loopRunning = 1;
$('#slide').stop().animate({marginLeft:px}, time, function(){
loopRunning = 0;
});
}

Well, to answer your question rather than provide advice on better ways to do it, I usually handle tasks like this by assigning a temporary class to denote that something is in the process of being animated. As somebody else said, the reason for the stuttering is because the scroll function is getting called multiple times, so you keep stopping and restarting the animation.
So you can try something like this (Fiddle):
var amountScrolled = 50;
$(window).scroll(function() {
if ($('#slide').hasClass('sliding')) {
return;
}
if ($(window).scrollTop() > amountScrolled) {
$('#slide').stop().addClass('sliding').animate({marginLeft:"0px"}, 500, function() {
$(this).removeClass('sliding');
});
} else {
$('#slide').stop().addClass('sliding').animate({marginLeft: "-400px"}, 500, function() {
$(this).removeClass('sliding');
});
}
});

Setting a jScrollPane to autoscroll left and right, but pause on click?

Fiddle: http://jsfiddle.net/RJShm/
I have a jScrollPane that currently scroll from left, to right, then back left, and stops. What I'd like is for this to continually scroll from left to right, the right to left, then repeat. I have this fairly close to working by using pane.bind('jsp-scroll-x'..., but I can't seem to get it to scroll back to the right after one cycle. Current code for that:
pane.bind('jsp-scroll-x', function (event, pos_x, at_left, at_right) {
if (at_right)
{
api.scrollToX(0);
$(this).unbind(event);
}
});
I would also like for this to stop autoscrolling when anything in the pane is clicked (scroll bar, arrows, content, anything), and it would preferably restart after a few seconds of no clicks.
So, in short, how do I:
Make the jScrollPane scroll left/right automatically
Stop autoscrolling when clicked
Restart autoscrolling after a few seconds of no clicks inside the pane
Thanks
EDIT: jScrollPane Settings, and api for your convenience.

I have updated the handler for toggling the infinite scroll and also implemented click handler to pause the scroll and resume after a timeout (5 seconds). See draft code below and check the DEMO: http://jsfiddle.net/p6jLt/
var defaultSettings = {
showArrows: true,
animateScroll: true,
animateDuration: 5000
},
pauseSettings = {
showArrows: true,
animateScroll: false
};
var pane = $('.scroll-pane').jScrollPane(defaultSettings);
var api = pane.data('jsp');
var isFirst = true,
posX = 0,
isLeft = false,
timer;
pane.bind('jsp-scroll-x', scrollFx)
.mousedown(function () {
//lets make sure the below is
//executed only once after automatic croll
if (posX != -1) {
$(this).unbind('jsp-scroll-x');
api.scrollToX(posX);
api.reinitialise(pauseSettings); //no animation
posX = -1;
}
}).mouseup(function () {
clearTimeout(timer); //clear any previous timer
timer = setTimeout(function () {
isFirst = true;
posX = 0; //reset the killer switch
api.reinitialise(defaultSettings); //animateed scroll
pane.bind('jsp-scroll-x', scrollFx); //rebind
api.scrollToX(isLeft ? 0 : api.getContentWidth()); //resume scroll
}, 5000);
});
var scroll = api.scrollToX(api.getContentWidth());
function scrollFx(event, pos_x, at_left, at_right) {
if (posX == -1) { //kill scroll
$(this).unbind(event);
return false;
}
if (at_right) {
api.scrollToX(0);
isLeft = true; //used for restart
} else if (at_left && !isFirst) {
api.scrollToX(api.getContentWidth());
isLeft = false; //used for restart
}
isFirst = false;
posX = pos_x;
}
Issues: The plugin is little buggy with scroll sometimes, but it doesn't break the infinite scroll. You may find the little hicks on scroll, but it works for the most part. Test it out thoroughly and see how it goes.

Dynamic divs and scrollTop

I have a single page site:
http://chiaroscuro.telegraphbranding.com/
Each section is dynamically sized based on the user's window. I'm trying to figure out how to have a jQuery smooth scroll function scroll to the top of each section when the link is clicked. It is working great for the first section, funding areas, where I just used a simple offset().top, but the others are not working because they don't know how far to scroll because the window size is always different.
I've been trying to get offset() or position() to work, but no dice. I appreciate any advice.
Here's my jQuery:
`
$(document).ready(function () {
var slowScrollFunding = $('#funding-areas').offset().top;
var slowScrollAbout = $('#about-us').offset().top;
var slowScrollProjects = $('#our-projects').offset().top + 600;
panelOpen = true;
$('#anchor-funding-areas').click(function(event) {
event.preventDefault();
if(panelOpen == true) {
$('#slide-panel-content').stop(true, true).animate({height: '0px'}, 600, function() {
$('#panel-content-container').hide();
$('.scrollableArea').css('z-index', '11');
// Scroll down to 'slowScrollTop'
$('html, body, #home-wrap').animate({scrollTop:slowScrollFunding}, 1000);
panelOpen = false;
});
}else{
$('html, body, #home-wrap').animate({scrollTop:slowScrollFunding}, 1000);
};
});
$('#anchor-aboutus').click(function(event) {
event.preventDefault();
if(panelOpen == true) {
$('#slide-panel-content').stop(true, true).animate({height: '0px'}, 600, function() {
$('#panel-content-container').hide();
$('.scrollableArea').css('z-index', '11');
// Scroll down to 'slowScrollTop'
$('html, body, #aboutus-wrap').animate({scrollTop:slowScrollAbout}, 1000);
panelOpen = false;
});
}else{
$('html, body, #home-wrap').animate({scrollTop:slowScrollAbout}, 1000);
};
});
$('#anchor-ourprojects').click(function(event) {
event.preventDefault();
if(panelOpen == true) {
$('#slide-panel-content').stop(true, true).animate({height: '0px'}, 600, function() {
$('#panel-content-container').hide();
$('.scrollableArea').css('z-index', '11');
// Scroll down to 'slowScrollTop'
$('html, body, #home-wrap').animate({scrollTop:slowScrollProjects}, 1000);
panelOpen = false;
});
}else{
$('html, body, #home-wrap').animate({scrollTop:slowScrollProjects}, 1000);
};
});
$('#header-logo').add('.homelink').click(function() {
if(panelOpen == false) {
$('.scrollableArea').css('z-index', '0');
$('#panel-content-container').show();
$('#slide-panel-content').stop(true, true).animate({height: '389px'}, 600, function() {
// Scroll down to 'slowScrollTop'
panelOpen = true;
});
};
});
});
`

$.offset and $.position can be a little unreliable, especially if you have lots of complicated layouts going on - as your page does. What I've used in the past is the following trick:
var de = document.documentElement ? document.documentElement : document.body;
var elm = $('get_your_anchor_element').get(0);
var destScroll, curScroll = de.scrollTop;
/// check for the function scrollIntoView
if ( elm.scrollIntoView ) {
/// get the browser to scrollIntoView (this wont show up yet)
elm.scrollIntoView();
/// however the new scrollTop is calculated
destScroll = de.scrollTop;
/// then set the scrollTop back to where we were
de.scrollTop = curScroll;
/// you now have your correct scrollTop value
$(de).animate({scrollTop:destScroll});
}
else {
/// most browsers support scrollIntoView so I didn't bother
/// with a fallback, but you could just use window.location
/// and jump to the anchor.
}
The above can occur on the click event. The only thing that needs to be improved is that different browsers scroll on different base elements (body or html). When I used this I had my own element that was scrollable so I didn't need to work out which one the agent was using... When I get a second I'll see if I can find a good bit of code for detecting the difference.
The above has worked in all the modern browsers I've tested (Firefox, Safari, Chrome) however I didn't need to support Internet Explorer so I'm not sure with regard to that.
update:
I'm not quite sure what is going on with your implementation - it is possible that the page is so heavy with content that you actually can see the .scrollIntoView() happening - this has never been my experience, but then I didn't have so much going on on-screen. With that in mind, I've implemented a bare bones system that I would advise you use and build each extra part you need into it:
http://pebbl.co.uk/stackoverflow/13035183.html
That way you know you have a working system to start with, and will easily detect what it is that stops it from working. With regards to chiaro.js your implementation seems to be ok - if a little exploded over many different areas of the file - however this part is slightly erroneous:
$('#anchor-aboutus').click(function() {
event.preventDefault();
if(panelOpen == true) {
$('#slide-panel-content')
.stop(true, true)
.animate({height: '0px'}, 600, function() {
$('#panel-content-container').hide();
$('.scrollableArea').css('z-index', '11');
elm.scrollIntoView(true)
.animate({scrollTop:destScroll}, 1000);
panelOpen = false;
});
}else{
elm.scrollIntoView(true).animate({scrollTop:destScroll});
};
});
In the code above you will only get the correct value of destScroll if panelOpen === true. Ahh, actually I've also spotted another problem - which will explain why it's not working:
elm.scrollIntoView(true)
.animate({scrollTop:destScroll}, 1000);
The above code is mixing pure JavaScript and jQuery, the elm var is a normal DOM element (this supports the scrollIntoView method). But you are then attempting to chain the animate method of jQuery into the mix - you should also be triggering the animate method on the element responsible for the scrollbar. What you should use is as follows:
$('#anchor-aboutus').click(function(e) {
var currentScroll, destScroll;
e.preventDefault();
if(panelOpen == true) {
$('#slide-panel-content')
.stop(true, true)
.animate({height: '0px'}, 600, function() {
$('#panel-content-container').hide();
$('.scrollableArea').css('z-index', '11');
currentScroll = de.scrollTop;
elm.scrollIntoView(true);
destScroll = de.scrollTop;
de.scrollTop = currentScroll;
$(de).animate({scrollTop:destScroll}, 1000);
panelOpen = false;
});
}else{
currentScroll = de.scrollTop;
elm.scrollIntoView(true);
destScroll = de.scrollTop;
de.scrollTop = currentScroll;
$(de).animate({scrollTop:destScroll}, 1000);
};
});
However, what you will also need to do is make sure your de element points to the right element - either html or body depending on the browser - for this you can use this:
var de;
/// calculate which element is the scroller element
$('body, html').each(function(){
if ( this.scrollHeight > this.offsetHeight ) {
de = this;
return false;
}
});
alert( $(de).is('body') ) /// will be true for Chrome, false for Firefox.
You will need to use this code in place of the following code:
var de = document.documentElement ? document.documentElement : document.body;
The reason for changing the code you were using is as follows:
/// store the current scroll position from the de element
currentScroll = de.scrollTop;
/// get the browser to do the scrollTo calculation
elm.scrollIntoView(true);
/// store where the browser scrolled to behind the scenes
destScroll = de.scrollTop;
/// reset our scroll position to where we were before scrollIntoView()
/// if you don't reset then the animation will happen instantaneously
/// because that is what scrollIntoView does.
de.scrollTop = currentScroll;
/// wrap the normal dom element de with jquery and then animate
$(de).animate({scrollTop:destScroll}, 1000);

Cancel scrolling after user interaction

My webpage animates scrolling when users click on links to the same page. I want to cancel this animation as soon as the user tries to scroll (otherwise the user and the browser are fighting for control) – no matter whether with the mouse wheel, the keyboard or the scrollbar (or any other way – are there other ways of scrolling?). I managed to cancel the animation after the mouse wheel or keyboard are used, how do I get this working with the scrollbar?
Here is how my code looks for the keyboard:
$(document.documentElement).keydown( function (event) {
if(event.keyCode == 38 || 40) stopScroll();
});
function stopScroll() {
$("html, body").stop(true, false);
}
I also tried a more elegant way of doing this by using scroll(), the problem is that scroll() catches everything including the animated and automated scrolling. I could not think of any way to let it catch all scrolling except the animated scrolling.

you need animation marker, something like this
$("html, body").stop(true, false).prop('animatedMark',0.0).animate({scrollTop : top, animatedMark: '+=1.0'})
Here is the code, the code was mix of GWT and javascript so moved it to js, not fully tested, please try it
var lastAnimatedMark=0.0;
function scrollToThis(top){
// Select/ stop any previous animation / reset the mark to 0
// and finally animate the scroll and the mark
$("html, body").stop(true, false).prop('animatedMark',0.0).
animate({scrollTop : top, animatedMark: '+=1.0'}
,10000,function(){
//We finished , nothing just clear the data
lastAnimatedMark=0.0;
$("html, body").prop('animatedMark',0.0);
});
}
//Gets the animatedMark value
function animatedMark() {
var x=$("html, body").prop('animatedMark');
if (x==undefined){
$("html, body").prop('animatedMark', 0.0);
}
x=$("html, body").prop('animatedMark');
return x;
};
//Kills the animation
function stopBodyAnimation() {
lastAnimatedMark=0;
$("html, body").stop(true, false);
}
//This should be hooked to window scroll event
function scrolled(){
//get current mark
var currentAnimatedMark=animatedMark();
//mark must be more than zero (jQuery animation is on) & but
//because last=current , this is user interaction.
if (currentAnimatedMark>0 && (lastAnimatedMark==currentAnimatedMark)) {
//During Animation but the marks are the same !
stopBodyAnimation();
return;
}
lastAnimatedMark=currentAnimatedMark;
}
Here is the blog about it
http://alaamurad.com/blog/#!canceling-jquery-animation-after-user-interaction
Enjoy!

Here's a jquery function that should do the trick:
function polite_scroll_to(val, duration, callback) {
/* scrolls body to a value, without fighting the user if they
try to scroll in the middle of the animation. */
var auto_scroll = false;
function stop_scroll() {
if (!auto_scroll) {
$("html, body").stop(true, false);
}
};
$(window).on('scroll', stop_scroll);
$("html, body").animate({
scrollTop: val
}, {
duration: duration,
step: function() {
auto_scroll = true;
$(window).one('scroll', function() {
auto_scroll = false;
});
},
complete: function() {
callback && callback();
},
always: function() {
$(window).off('scroll', stop_scroll);
}
});
};

It's not very elegant, but you could use a flag of some kind to detect what type of scrolling you're dealing with (animated or 'manual') and always kill it when it's animated. Here's an untested example:
var animatedScroll = false;
// you probably have a method looking something like this:
function animatedScrollTo(top) {
// set flag to true
animatedScroll = true;
$('html').animate({
scrollTop : top
}, 'slow', function() {
// reset flag after animation is completed
animatedScroll = false;
});
}
function stopScroll() {
if (animatedScroll) {
$("html, body").stop(true, false);
}
}