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JS Scroll window while mouseover

I would like to scroll up or down the window while the mouse is over a specific element.
What I have so far basically works but it's not "smooth". It starts and stops on and on, not looking nice. Do you have any idea how to make a more constant smooth scrolling?
This is my code:
doScroll = 0;
$(".helperDown").mouseenter(function() {
scrollHandler = setInterval( function() {
console.log('scrolling down...');
if(doScroll == 0) {
doScroll = 1;
$("html, body").animate({scrollTop: fromTop+50}, 200, 'linear', function() {
doScroll = 0;
});
}
}, 200);
});
$(".helperDown").mouseleave(function() {
clearInterval(scrollHandler);
});
.helperDown is the area where the mouse has to be in to start scrolling. fromTop is always recalculated after a scroll event.

You can not start a series of animation and expect a smooth scrolling. What you need is to start one animation only by pre-calculating the distance this animation will cover. Also, jQuery has a nice wrapper for mouseenter and mouseleave -combined. It's the hover() function with two functions as its parameter. The following code block will solve your issue.
Also, this plnkr has both the up and down scroll feature:
https://plnkr.co/edit/WoneJ8?p=preview
$(function () {
// change this value as per your need
var distancePerSec = 1000;
$(".helperDown").hover(function () {
var h = $("body").height();
var targetScrollTop = h - $(window).height();
var distanceToTravel = targetScrollTop - $(window).scrollTop();
var animationDuration = (distanceToTravel / distancePerSec) * 1000;
$("html, body").animate({
scrollTop: targetScrollTop
}, animationDuration, 'linear');
}, function () {
// stop the animation
$("html, body").stop();
});
})

How to scroll once in $(window).scroll() have another scroll command

I have a vertical photo viewer
and i need a scroll effect is once a page height when mouse wheel down.
so i have following code
$(document).ready(function() {
$(window).scroll(function () {
var H = $(window).height();
var st = $(this).scrollTop();
$("html, body").animate({ scrollTop: H + st }, 500, function () {
console.log("finish scroll");
});
});
});
But when i scroll once, it will repeat again and again until to the bottom.
How can i solve this problem?
Thanks in advance.

I used a counter and a timer so that the counter waits half a second after the scroll has finished..
http://jsfiddle.net/beardedSi/p45rH/1/
$(document).ready(function () {
var H = $(window).height(),
go = true;
console.log(H);
//just for visual, set the height of boxes to be same as window height
//to check it is all working
$('.box').css('height', H + "px");
function scroller() {
$("html, body").animate({
scrollTop: '+=' + H
}, 400, function () {
console.log("finished");
setTimeout(function () {
go = true;
}, 400);
});
}
$(document).on('scroll', function (e) {
e.preventDefault();
if (go) {
go = false;
scroller();
}
});
});

The problem is the animation make a scroll event too. so you have a scrolling loop.
To resolve that, you can add a flag.
It's not the best way to solve your problem but you can do this => http://jsbin.com/qagayopu/2/edit

JQuery ScrollTop in the middle of an animation?

I have 2 containers whose widths change. Inside them, I have clickable elements. When a container is clicked, it resizes in an animation. I want to make it so that when a clickable element is clicked, its container resizes and scrolls to the clicked element. Here's a fiddle that shows this: http://jsfiddle.net/w7H3M/1/
However, it scrolls to the wrong position because of the resizing. Here's the event handler for the click:
<div id=left>...</div>
<div id=right>...</div>
$('#left').on('click', 'a', function () {
var node = $(this);
$('#left').animate({
width: 0.75 * $(document).width()
}, 800);
$('#right').animate({
width: 0.25 * $(document).width()
}, 800);
$('body').animate({
scrollTop: node.offset().top
}, 800);
});
$('#right').on('click', 'a', function () {
var node = $(this);
$('#left').animate({
width: 0.25 * $(document).width()
}, 800);
$('#right').animate({
width: 0.75 * $(document).width()
}, 800);
$('body').animate({
scrollTop: node.offset().top
}, 800);
});

Effectively, it does not work correctly because of the animation. The offset of the node you want to show at the top of the screen will change when the div expands. To achieve what you want, you need to set the scrollTop property when the animation completes. You can achieve this using the complete handler of jQuery.animate(). I've forked your jsfiddle to show you it. The only problem is that the two animationw now play one after the other instead of simultaneously.
$(document).ready(function () {
// generate content
var str = '';
for (i = 1; i < 100; i++) {
str += '<p>' + x100(i) + '</p>';
}
$('#left').html(str);
$('#right').html(str);
// end generate content
$('#left').on('click', 'p', function () {
var node = $(this);
$('#left').animate({
width: 0.75 * $(document).width(),
}, 800, 'swing', function() {
$('body, html').animate({scrollTop: node.offset().top}, 800);
});
$('#right').animate({
width: 0.25 * $(document).width()
}, 800);
});
$('#right').on('click', 'p', function () {
var node = $(this);
$('#left').animate({
width: 0.25 * $(document).width()
}, 800);
$('#right').animate({
width: 0.75 * $(document).width()
}, 800, 'swing', function() {
$('body, html').animate({scrollTop: node.offset().top}, 800);
});
});
});

Firing an animation when aligned

I am creating a splitscrolling website and it's working great. But i have one problem, when the user stops scrolling it fires a function called alignWhenIdle and what this does is align the columns so they become "one".
Now that is working nicely but i can't seem to target a specific part of the column that aligns. let's say when the number 2 column aligns ( see image ) i want to be able to fire an animation. I tried using a callback but that fires a function every time the columns are aligned.
This is my JS:
(function ($) {
var top = 0;
var contentHeight, contents, totalHeight;
var locked = false;
var timeout;
var align = function () {
var pos = (top + $(window).scrollTop());
var snapUp = 0 - (pos % contentHeight) < (contentHeight / 2);
var multiplier = snapUp
? Math.ceil(pos / contentHeight)
: Math.floor(pos / contentHeight);
var newTop = contentHeight * multiplier;
$('html, body').animate({ scrollTop: newTop + totalHeight }, 200);
locked = false;
};
var reset = function () {
contentHeight = $('.right').height();
contents = $('.right > .content').length;
totalHeight = contentHeight * (contents - 1);
top = (0 - totalHeight);
};
var scrollRight = function () {
$('.right').css('top', (top + $(window).scrollTop()) + 'px');
};
var alignWhenIdle = function (delay) {
clearTimeout(timeout);
timeout = setTimeout(align, delay);
};
$(document).on('ready', function () {
reset();
scrollRight();
});
$(window).on('scroll', function () {
locked = true;
scrollRight();
});
$(window).on('mouseup', function (e) {
if (locked) {
align();
}
});
$(window).resize(function () {
locked = true;
reset();
scrollRight();
alignWhenIdle(300);
});
$(window).on('mousewheel', function (e) {
alignWhenIdle(300);
});
$(window).on("keyup", function (e) {
alignWhenIdle(300);
});
})(jQuery);
http://jsfiddle.net/ev3B8/
Any help is much appreciated,
Cheers

See http://jsfiddle.net/5T9Y8/
Scroll till the column 2 and see result...
In the method align I've added a callback:
$('html, body').animate({ scrollTop: newTop + totalHeight }, 200, function(){
$(".animate").animate({ marginLeft: "200px" },300);
});
Works well, did you need exactly that?
EDIT
You should just check for some condition.
E.g. based on this solution Check if element is visible after scrolling you can build this:
$('html, body').animate({ scrollTop: newTop + totalHeight }, 200, function(){
if (isScrolledIntoView(".animate")) $(".animate").animate({ marginLeft: "200px" },300);
});
See updated solution here http://jsfiddle.net/5T9Y8/1/
This is only one way, I'm really sure there is a way to do it even better. E.g. you can calculate the current elements which are shown and then just find the things only inside of them.

I tried using a callback but that fires a function every time the columns are aligned.
Use one method for functioning only once instead of on.

Scroll to Top and Scroll to Bottom in Jquery

I tried to implement the scroller with top to bottom and bottom to top with jquery. I recently tried with percent.
From the Top to bottom with pixel is seems ok.(Means it works) for the bottom to top is only make scroll not completely finish if i mention percentage as 100
$('#spnTop').on("click",function(){
var percentageToScroll = 100;
var percentage = percentageToScroll/100;
var height = jQuery(document).height();
var documentHeight = $(document).height();
var scroll = $(window).scrollTop();
alert(scroll);
var scrollAmount = Math.round((height) * percentageToScroll/ 100)-scroll;
//alert(point);
alert(scrollAmount);
$('html,body').animate({ scrollTop: scrollAmount }, 'slow', function () {
alert("reached top"); });
});
Here is the fiddle.
For Example:
percentageToScroll is now 100 but the ending of scroll is not completely finish. (from bottom to top)
For top to bottom is 100 then it completely scroll to bottom of the page.
I am not sure how to make it workable.
Thanks.
Vicky

What about this?
$('#spnTop').on("click",function(){
var percentageToScroll = 100;
var percentage = percentageToScroll/100;
var height = $(document).scrollTop();
var scrollAmount = height * (1 - percentage);
alert(scrollAmount);
$('html,body').animate({ scrollTop: scrollAmount }, 'slow', function () {
alert("reached top"); });
});
$('#spnbottom').on("click",function() {
var percentageToScroll = 100;
var height = $(document).innerHeight();
var scrollAmount = height * percentageToScroll/ 100;
alert(scrollAmount);
var overheight = jQuery(document).height() - jQuery(window).height();
//alert(overheight);
jQuery("html, body").animate({scrollTop: scrollAmount}, 900);
});
Fiddle here

As I specified in comment I prepared a Demo
$(document).on("click","#spnTop",function(){
$('html,body').animate({scrollTop: 0}, 1500);
});
$(document).on("click","#spnbottom",function() {
var window_height = $(window).height();
var document_height = $(document).height();
$('html,body').animate({ scrollTop: window_height + document_height },1500);
});
I hope it may help you

jQuery(document).ready(function($){
$('#goToTop').on("click",function(){
$("html, body").animate({ scrollTop: 0 }, 2000);
return false;
});
$('#goToBottom').on("click",function() {
$("html, body").animate({scrollTop: $(document).innerHeight()}, 2000);
return false;
});
});

Now see you need the percentages
See demo here:
http://jsfiddle.net/a3g4d/
$('#spnTop').on("click",function(){
var percentage = 100;
var height = $(document).height();
var remove = +height / +100 * +percentage;
var spaceFromTop = +height - +remove;
$('html,body').animate({ scrollTop: spaceFromTop }, 'slow', function () {});
});

You can also use the span positions if you have top and bottom span always.
$('#spnTop').on("click",function(){
$('html,body').animate({
scrollTop: $("#spnbottom").offset().top
}, 'slow', function () {
alert("reached top");
});
});
http://jsfiddle.net/4qLvC/8/

I hope something like this :) might help you
$('#spnTop').on("click",function(){
$('html,body').animate(
{ scrollTop: 0 },
'slow',
function () {});
});
$('#spnbottom').on("click",function() {
var window_height = $(window).height();
var document_height = $(document).height();
$('html,body').animate(
{ scrollTop: window_height + document_height },
'slow',
function () {});
});
Use this link to try it out : demo

$(function () {
$("#scrollToBottom").click(function () {
$('html, body').animate({ scrollTop: window.screen.height }, 400);
});
$("#scrollToTop").click(function () {
$('html, body').animate({ scrollTop: 0 }, 400);
});
});