Develop Reference

Scroll snapping to a page section

So I have two sections of content near the top of my page and I’d like for users who have scrolled down to near the top of the second section to get “scroll snapped” to the top of the second one once they have stopped scrolling.
I think it should be possible using jQuery but I haven’t been able to figure it out. Here are my examples:
Without my attempt: http://codepen.io/jifarris/pen/gaVgBp
With my broken attempt: http://codepen.io/jifarris/pen/gaVgQp
Basically I can’t figure out how to make it try scrolling to the spot only once, after scrolling has stopped. It’s kind of just freaking out.
I love how the recently introduced scroll snap points CSS feature handles scroll snapping and I’d almost prefer to use it – for the browsers that support it, at least – but it seems like it only works for items that take up 100% of the viewport height or width, and it seems like it’s for scrolling within an element, not the page itself.
The top section has a fixed height, so this really can be handled with pixel numbers.
And for reference, here’s the heart of the code from my attempt:
$(function() {
$(document).on('scroll', function() {
var top = $(document).scrollTop();
if (top > 255 && top < 455) {
$('html, body').animate({scrollTop: '356'}, 500);
$('body').addClass('hotzone');
} else {
$('body').removeClass('hotzone');
}
});
});

KQI's answer contains most of the steps required to create a well functioning section-scroll for use in your application/webpage.
However, if you'd just want to experiment yourself, developing your script further, the first thing you'll have to do is add a timeout handler. Otherwise your logic, and therefor scrollAnimation, will trigger every single pixel scrolled and create a buggy bouncing effect.
I have provided a working example based on your script here:
http://codepen.io/anon/pen/QjepRZ?editors=001
$(function() {
var timeout;
$(document).on('scroll', function() {
clearTimeout(timeout);
timeout = setTimeout(function() {
var top = $(document).scrollTop();
if (top > 255 && top < 455) {
$('body').animate({
scrollTop: '356'
}, 500);
$('body').addClass('hotzone');
} else {
$('body').removeClass('hotzone');
}
}, 50);
});
});
Good luck!

All right, there are couple of things you gonna have to deal with to get a good result: which are performance, call stack queue, easing.
Performance wise you should drop jQuery animate and use VelocityJs which gives a smoother transition, better frame per second (fps) to avoid screen glitches especially on mobiles.
Call stack: you should wrap whatever logic you have to animate the scrolltop with 'debounce' function, set the delay for let say 500mm and check the scrolling behavior. Just so you know, the 'scroll' listener your using is firing on each pixel change and your script will go crazy and erratic. (It is just gonna be a moment of so many calc at the same time. Debounce will fix that for you)
Easing: make the transition looks cool not just dry snappy movement.
Remember, 'easing' with Velocity starts with 'mina.' i.e.
'Mina.easingFnName'
Finally, your logic could be right, i am in my phone now cannot debug it but try to simplify it and work with a single problem at once, be like i.e.
If ( top > 380 ) // debounce(...)

Revolution Slider - Advance once per mouse scroll

EDIT: Revolution Slider recently updated to Version 5 which by default supports mouse scrolling between slides without the need for additional javascript by the user and I've found it to work flawlessly.
Original Question:
I'm using a full screen Revolution Slider and by using the code found on the developers site I've managed to get the slides to advance using a mousewheel scroll.
The problem is that the slider is advancing more than one slide at a time depending on how much the user scrolls. I need the slide to only scroll once per mousewheel event. I tried using the solution found here but couldn't get it to work: Removing event after one scroll
I'm very new to Javascript so any help is much appreciated.
Here is the code I am currently using
(function() {
var slider = revapi1;
slider.parent().on('mousewheel DOMMouseScroll', function(event) {
if(event.originalEvent.wheelDelta > 0 || event.originalEvent.detail < 0) {
slider.revprev();
}
else {
slider.revnext();
}
});
})()

revprev() and revnext() is where moves happen.
Deeper you should find something like speed, steps_length...

carousel trigger when continuous scrolling not working

The carousel (caroufredsel) scroll (check this for example) continously to the left. When I hover to an arrow to the right it will stop scrolling then it will reverse it's direction. I tried using custom events but it appears that it's not working. Here's a code of the carousel.
$('#gallery').carouFredSel({
width: "variable",
auto: {
items : 4,
duration :"40000",
easing :"linear",
timeoutDuration :0,
pauseOnHover :"immediate"
},
items: {
visible: 3
}
});
Now my custom event that will cause the carousel to reverse is direction is like this. But it's not working until the whole items where finished scrolling. What I want to achieve is to instantaneously reverse the direction when hovering.
$('a.prev').hover(function()
{
$('#gallery').trigger("pause");
$('#gallery').trigger("configuration",["direction",right]);
$('#gallery').trigger("play");
}
The code above doesn't work and I've tried different events that will simulate the reversal of scrolling but had no luck with it.
If there's no workaround for this. I'm willing to change another plugin that will easily do the work. If you know something that can do it easily please leave your suggestions. Thank you very much!

That totally depends how the carousel is implemented. A possible solution might be to stop the eventPropagation. It may or may not work depending on the implementation of the carousel.
$('a.prev').hover(function(event)
{
event.stopPropagation();
$('#gallery').trigger("pause");
$('#gallery').trigger("configuration",["direction",right]);
$('#gallery').trigger("play");
}

How do I stop a bouncy JQuery animation?

In a webapp I'm working on, I want to create some slider divs that will move up and down with mouseover & mouseout (respectively.) I currently have it implemented with JQuery's hover() function, by using animate() and reducing/increasing it's top css value as needed. This works fairly well, actually.
The problem is that it tends to get stuck. If you move the mouse over it (especially near the bottom), and quickly remove it, it will slide up & down continuously and won't stop until it's completed 3-5 cycles. To me, it seems that the issue might have to do with one animation starting before another is done (e.g. the two are trying to run, so they slide back and forth.)
Okay, now for the code. Here's the basic JQuery that I'm using:
$('.slider').hover(
/* mouseover */
function(){
$(this).animate({
top : '-=120'
}, 300);
},
/* mouseout*/
function(){
$(this).animate({
top : '+=120'
}, 300);
}
);
I've also recreated the behavior in a JSFiddle.
Any ideas on what's going on? :)
==EDIT== UPDATED JSFiddle

It isn't perfect, but adding .stop(true,true) will prevent most of what you are seeing.
http://jsfiddle.net/W5EsJ/18/
If you hover from bottom up quickly, it will still flicker because you are moving your mouse out of the div causing the mouseout event to fire, animating the div back down.
You can lessen the flicker by reducing the delay, however it will still be present until the delay is 0 (no animation)
Update
I thought about it and realized that there is an obvious solution to this. Hoverintent-like functionality!
http://jsfiddle.net/W5EsJ/20/
$(document).ready(function() {
var timer;
$('.slider').hover(
/* mouseover */
function(){
var self = this;
timer = setTimeout(function(){
$(self).stop(true,true).animate({
top : '-=120'
}, 300).addClass('visible');
},150)
},
/* mouseout*/
function(){
clearTimeout(timer);
$(this).filter(".visible").stop(true,true).animate({
top : '+=120'
}, 300).removeClass("visible");
}
);
});

You could use .stop() and also use the outer container position
$(document).ready(function() {
$('.slider').hover(
/* mouseover */
function(){
$(this).stop().animate({
top : $('.outer').position().top
}, 300);
},
/* mouseout*/
function(){
$(this).stop().animate({
top : $('.outer').position().top + 120
}, 300);
}
);
});
​
DEMO
Hope this helps

Couldn't reproduce your issue but I believe that hover is getting called multiple times. To work around this you can check if the div is already in animation. If yes, then don't run another animation again.
Add following piece of code to check if the div is already 'animating':
if ($(this).is(':animated')) {
return;
}
Code: http://jsfiddle.net/W5EsJ/2/
Reference:http://api.jquery.com/animated-selector/

I understand the problem and reproduced it, it happens when hovering from the bottom up. The hovering with the mouse is what's causing the problem since the animation function will be called when the mouse hovers over the image. You need to control what happens here by using mouse enter and mouse leave, check out a similar example: Jquery Animate on Hover

The reason it's like that is because the hover is getting queued up causing it to slide up and down multiple times. There's a plug-in called hoverIntent which fixes the issue. http://cherne.net/brian/resources/jquery.hoverIntent.html
If you do decide to use hoverIntent, the only thing you have to change in your code is .hover > .hoverIntent

How to solve element flicker while scrolling with parallax effect in JavaScript?

I am trying to re-create website with parallax effect using JavaScript. That means that I have two or more layers, that are moving different speeds while scrolling.
In my case I'm moving only one layer, the other one remains static:
layer 1 = website text;
layer 2 = element background;
for this I'm using simple source code (with jQuery 1.6.4):
var docwindow = $(window);
function newpos(pos, adjust, ratio){
return ((pos - adjust) * ratio) + "px";
}
function move(){
var pos = docwindow.scrollTop();
element.css({'top' : newpos(pos, 0, 0.5)});
}
$(window).scroll(function(){
move();
});
The Problem:
- All calculations are done right and the effect "works" as expected. But there is some performance glitch under some browsers (Chrome MAC/Windows, Opera MAC, IE, paradoxically not Safari).
What do I see during scrolling?
- While scrolling the background moves in one direction together with scroll, but it seems to occasionally jump few pixels back and then forth, which creates very disturbing effect (not fluid).
Solutions that I tried:
- adding a timer to limit scroll events
- using .animate() method with short duration instead of .css() method.
I've also observed, that the animation is smooth when using .scrollTo method (scrollTo jQuery plugin). So I suspect that there is something wrong with firing scroll events (too fast).
Have you observed the same behavior?
Do you know, how to fix it?
Can you post a better solution?
Thanks for all responses
EDIT #1:
Here you can find jsfiddle demonstration (with timer): http://jsfiddle.net/4h9Ye/1/

I think you should be using scrollTop() instead and change the background position to fixed. The problem is that setting it to absolute will make it move by default when you scroll up or down.
The flicker occurs because the position is updated as part of the default browser scroll and updated again as part of your script. This will render both positions instead of just the one you want. With fixed, the background will never move unless you tell it so.
I've created a demo for you at http://jsfiddle.net/4h9Ye/2/ .