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Pure Javascript, How to detect if scrollTop will scroll to the bottom of the page?

I have a function which basically runs when an arrow with the class 'downArrow' is click. The function will find the parent of that arrow then find the next sibling with a class of 'scrollPoint' and then scroll to that area. Everything I just described works fine for me the issue I am having is if the bottom of the document hits the bottom of my viewport before the top of the element I am scrolling to hits the top of the viewport it just glitches out and scrolls back to the very top of the document. So I think What I need to do is detect if this scenario is going to happen and then set a max scroll value so the scroll functions doesnt try to scroll passed the bottom of the document.
How would I detect if the bottom of the document will be visible on the viewport and prevent from scrolling that far?
I will provide my code below in hopes that it will help, if you have any questions or need more clarification of what I am asking for just let me know. Thanks
This is my component although for what i am asking only the scrollTo function is really relevant
exports.init = init;
function init (options){
var downArrows = document.querySelectorAll(options.selector);
downArrows.forEach(triggerScrollHandler);
}
function scrollTo(element, to, duration) {
if (duration < 0) return;
var difference = to - element.scrollTop;
var perTick = difference / duration * 10;
setTimeout(function() {
element.scrollTop = element.scrollTop + perTick;
if (element.scrollTop === to) return;
scrollTo(element, to, duration - 10);
}, 10);
}
function scrollHandler (e) {
e.preventDefault();
var el = this,
scrollPoint = findSibling(el),
offsetVal = scrollPoint.getBoundingClientRect(),
windowOffset = window.pageYOffset;
offsetVal = offsetVal.top + windowOffset - 1;
scrollTo(document.body, offsetVal, 600);
}
function findParent(el) {
while (el && el.parentNode) {
el = el.parentNode;
if (el.tagName) {
return el;
}
}
return null;
}
function findSibling (el) {
var parent = findParent(el),
siblings = document.querySelectorAll('.scrollPoint'),
scrollTo;
siblings.forEach(function (currentSib, i) {
if(scrollTo == 'found'){
scrollTo = currentSib;
}
if(currentSib == parent){
scrollTo = 'found'
}
});
return scrollTo;
}
function triggerScrollHandler (el) {
el.addEventListener('click', scrollHandler);
}
And this is where I call in my app.js
var scrollHandler = require('./components/scrollHandler.js');
(function(){
scrollHandler.init({
selector: '.downArrow'
});
}())

Put this in your scroll listener:
if (document.body.scrollHeight <= document.body.scrollTop + document.body.clientHeight ){
console.log('scrolled to bottom');
}
Simple, pure JS solution :)

jQuery do something until element hits top

I'm blurring out a div on scrolling using the following script. What's the best way to wrap it into something telling it: only do this until #element hits the views top and then stop it. Something like a max-val.
$(window).on('scroll', function () {
var blurrad = $(document).scrollTop()
blurrad = blurrad / 100;
$(".videodummy").css({"-webkit-filter": "blur("+blurrad+"px)","filter": "blur("+blurrad+"px)" })
});
UPDATE:
First of all, thanks for your help. I tried to do this:
var topdist = $('#indicator').offset().top
while ( topdist > 0 ) {
$(window).on('scroll', function () {
var blurrad = $(document).scrollTop()
blurrad = blurrad / 100;
$(".videodummy").css({"-webkit-filter": "blur("+blurrad+"px)","filter": "blur("+blurrad+"px)" })
});
});
So if the div with #indicator hits top it should stop blurring, however this is not working at all.

Based on your try:
var topDist = $('#indicator').offset().top;
$(window).on('scroll', function () {
topDist = $('#indicator').offset().top;
if (topDist > 0) {
var blurrad = $(document).scrollTop();
blurrad = blurrad / 100;
$(".videodummy").css({"-webkit-filter": "blur("+blurrad+"px)",
"filter": "blur("+blurrad+"px)" });
}
});
I'd advice against a while since it's really not needed. Instead check with an if statement.

$('#element').offset().top
Will give you the distance from top

AngularJS - $anchorScroll smooth/duration

Reading the AngularJS docs I haven't figured out if $anchorScroll can have a duration/easing option to smooth scroll to elements.
It only says:
$location.hash('bottom');
// call $anchorScroll()
$anchorScroll();
I do not use jquery and don't want to; is there still a clever yet simple way to make or extend $anchorScroll in order to make scrolling more smooth?

Unfortunately this is not possible using $anchorScroll. As you discovered $anchorScroll doesn't have any options and doesn't work with $ngAnimate. In order to animate the scroll you would need to use your own service/factory or just straight javascript.
For the sake of self-learning I put together an example with a smooth scrolling service. There are probably better ways to do this so any feedback is encouraged.
To scroll to an element you attach a ng-click="gotoElement(ID)" to any element. I think an even better route would be to make this a directive.
Here's the working example on jsFiddle.
Update
There are now a number of third-party directives for accomplishing this.
https://github.com/oblador/angular-scroll.
https://github.com/d-oliveros/ngSmoothScroll
https://github.com/arnaudbreton/angular-smoothscroll
https://gist.github.com/justinmc/d72f38339e0c654437a2

You can also use the angular-scroll, link "https://github.com/durated/angular-scroll/". It is smooth scrolling also few easing functions to get a professional look.

The answer from Brett worked great for me. I did some small changes on his solution in terms of modularization and testability.
Here's is yet another working example on JsFiddle that includes the other version with testing included.
For testing, I'm using Karma and Jasmine. Signature has been slightly modified as follows:
anchorSmoothScroll.scrollTo(elementId, speed);
Where element is a mandatory attribute to scroll to and speed is optional where the default is 20 (as it was before).

You can also use ngSmoothScroll, link: https://github.com/d-oliveros/ngSmoothScroll.
Just include the smoothScroll module as a dependency and use it like this:
Click me!

None of the solutions here actually does what OP originally asked, that is, make $anchorScroll scrolling smoothly.
Difference between smooth scrolling directives and $anchroScroll is that it uses/modifies $location.hash(), which may be desirable in some cases.
Here is gist for simple module that replaces $anchorScroll scrolling with smooth scrolling. It uses https://github.com/oblador/angular-scroll library for the scrolling itself (replace it with something else if you want, it should be easy).
https://gist.github.com/mdvorak/fc8b531d3e082f3fdaa9
Note: It actually does not get $anchorScroll to scroll smoothly, but it replaces its handler for scrolling.
Enable it simply by referencing mdvorakSmoothScroll module in your application.

Alan, thank you. If anyone interested, I formatted it based on John Pappa standards.
(function() {
'use strict';
var moduleId = 'common';
var serviceId = 'anchorSmoothScroll';
angular
.module(moduleId)
.service(serviceId, anchorSmoothScroll);
anchorSmoothScroll.$inject = ['$document', '$window'];
function anchorSmoothScroll($document, $window) {
var document = $document[0];
var window = $window;
var service = {
scrollDown: scrollDown,
scrollUp: scrollUp,
scrollTo: scrollTo,
scrollToTop: scrollToTop
};
return service;
function getCurrentPagePosition(currentWindow, doc) {
// Firefox, Chrome, Opera, Safari
if (currentWindow.pageYOffset) return currentWindow.pageYOffset;
// Internet Explorer 6 - standards mode
if (doc.documentElement && doc.documentElement.scrollTop)
return doc.documentElement.scrollTop;
// Internet Explorer 6, 7 and 8
if (doc.body.scrollTop) return doc.body.scrollTop;
return 0;
}
function getElementY(doc, element) {
var y = element.offsetTop;
var node = element;
while (node.offsetParent && node.offsetParent !== doc.body) {
node = node.offsetParent;
y += node.offsetTop;
}
return y;
}
function scrollDown(startY, stopY, speed, distance) {
var timer = 0;
var step = Math.round(distance / 25);
var leapY = startY + step;
for (var i = startY; i < stopY; i += step) {
setTimeout('window.scrollTo(0, ' + leapY + ')', timer * speed);
leapY += step;
if (leapY > stopY) leapY = stopY;
timer++;
}
};
function scrollUp(startY, stopY, speed, distance) {
var timer = 0;
var step = Math.round(distance / 25);
var leapY = startY - step;
for (var i = startY; i > stopY; i -= step) {
setTimeout('window.scrollTo(0, ' + leapY + ')', timer * speed);
leapY -= step;
if (leapY < stopY) leapY = stopY;
timer++;
}
};
function scrollToTop(stopY) {
scrollTo(0, stopY);
};
function scrollTo(elementId, speed) {
var element = document.getElementById(elementId);
if (element) {
var startY = getCurrentPagePosition(window, document);
var stopY = getElementY(document, element);
var distance = stopY > startY ? stopY - startY : startY - stopY;
if (distance < 100) {
this.scrollToTop(stopY);
} else {
var defaultSpeed = Math.round(distance / 100);
speed = speed || (defaultSpeed > 20 ? 20 : defaultSpeed);
if (stopY > startY) {
this.scrollDown(startY, stopY, speed, distance);
} else {
this.scrollUp(startY, stopY, speed, distance);
}
}
}
};
};
})();

I am not aware of how to animate $anchorScroll . Here's how I do it in my projects:
/* Scroll to top on each ui-router state change */
$rootScope.$on('$stateChangeStart', function() {
scrollToTop();
});
And the JS function:
function scrollToTop() {
if (typeof jQuery == 'undefined') {
return window.scrollTo(0,0);
} else {
var body = $('html, body');
body.animate({scrollTop:0}, '600', 'swing');
}
log("scrollToTop");
return true;
}

We can use JQuery and Javascript with Directive to perform the scrolling to a specific div on anchor tag click.
Please check the working example on the below link -
https://stackoverflow.com/a/67513880/6656918

Get div position (top) in javascript?

One div i set the height in css using top:-26px;. I have other divs other places where i'd like to align with that div. I notice in jquery writing .css('top') gets me my css and not the y coord of the div. How do i get the absolute x,y position using javascript?

I will give you the vanilla solution.. don't complain.. add a [0] to your element and it's fixed! :P hope this helps.
function getOffset( el ) {
var _x = 0;
var _y = 0;
while( el && !isNaN( el.offsetLeft ) && !isNaN( el.offsetTop ) ) {
_x += el.offsetLeft - el.scrollLeft;
_y += el.offsetTop - el.scrollTop;
el = el.offsetParent;
}
return { top: _y, left: _x };
}
var x = getOffset( document.getElementById('yourElId') ).left;

You can use jQuery(element).offset().top
Hope it helps.

Try this code:
function getElementPosition(id) {
var offsetTrail = document.getElementById(id);
var offsetLeft = 0;
var offsetTop = 0;
while (offsetTrail) {
offsetLeft += offsetTrail.offsetLeft;
offsetTop += offsetTrail.offsetTop;
offsetTrail = offsetTrail.offsetParent;
}
return {
left: offsetLeft,
top: offsetTop
};
}​
It will return an object with left and top variables.
If you use JQuery try offset() method:
var pos = $("#element").offset();
console.log(pos.left)
console.log(pos.top)

Cross browser safe down to IE 8, possibly even 7 or 6:
function offset(el) {
var rect = el.getBoundingClientRect(),
scrollLeft = window.pageXOffset || document.documentElement.scrollLeft,
scrollTop = window.pageYOffset || document.documentElement.scrollTop;
return { top: rect.top + scrollTop, left: rect.left + scrollLeft }
}
var offsetEl = offset(document.getElementById('some_id'));
console.log(offsetEl.left, offsetEl.top);
Short and fast and no jQuery needed.

With standard JavaScript:
var elem=document.getElementById("elemID");
var top=elem.offsetTop;
var left=elem.offsetLeft;
With jQuery:
var top=$("#elemID").offset().top;
var left=$("#elemID").offset().left;

Use jQuery(element).offset()
Hope it helps.
For example
var elementPosition = jQuery(element).offset();
var elementTopPositon = elementPosition.top;

var MyElement = document.getElementById("...Your_DIV_Control...");
var top = MyElement.getBoundingClientRect().top;

Check if element is visible on screen [duplicate]

This question already has answers here:
Closed 11 years ago.
Possible Duplicate:
jQuery - Check if element is visible after scroling
I'm trying to determine if an element is visible on screen. In order to to this, I'm trying to find the element's vertical position using offsetTop, but the value returned is not correct. In this case, the element is not visible unless you scroll down. But despite of this, offsetTop returns a value of 618 when my screen height is 703, so according to offsetTop the element should be visible.
The code I'm using looks like this:
function posY(obj)
{
var curtop = 0;
if( obj.offsetParent )
{
while(1)
{
curtop += obj.offsetTop;
if( !obj.offsetParent )
{
break;
}
obj = obj.offsetParent;
}
} else if( obj.y )
{
curtop += obj.y;
}
return curtop;
}
Thank you in advance!

--- Shameless plug ---
I have added this function to a library I created
vanillajs-browser-helpers: https://github.com/Tokimon/vanillajs-browser-helpers/blob/master/inView.js
-------------------------------
Intersection Observer
In modern browsers you can use the IntersectionObserver which detects where an element is on the screen or compared to a parent.
The Intersection Observer API provides a way to asynchronously observe changes in the intersection of a target element with an ancestor element or with a top-level document's viewport.
Today I would probably lean toward this API if I need to detect and react to when an element has entered or exited the screen.
But for a quick test/lookup when you just want to verify if an emelemt is currently on screen I would go with the version just below using the getBoundingClientRect.
Using getBoundingClientRect
Short version
This is a lot shorter and should do it as well:
function checkVisible(elm) {
var rect = elm.getBoundingClientRect();
var viewHeight = Math.max(document.documentElement.clientHeight, window.innerHeight);
return !(rect.bottom < 0 || rect.top - viewHeight >= 0);
}
with a fiddle to prove it: http://jsfiddle.net/t2L274ty/1/
Longer version
And a version with threshold and mode included:
function checkVisible(elm, threshold, mode) {
threshold = threshold || 0;
mode = mode || 'visible';
var rect = elm.getBoundingClientRect();
var viewHeight = Math.max(document.documentElement.clientHeight, window.innerHeight);
var above = rect.bottom - threshold < 0;
var below = rect.top - viewHeight + threshold >= 0;
return mode === 'above' ? above : (mode === 'below' ? below : !above && !below);
}
and with a fiddle to prove it: http://jsfiddle.net/t2L274ty/2/
A more traditional way to do it
As BenM stated, you need to detect the height of the viewport + the scroll position to match up with your top position. The function you are using is ok and does the job, though its a bit more complex than it needs to be.
If you don't use jQuery then the script would be something like this:
function posY(elm) {
var test = elm, top = 0;
while(!!test && test.tagName.toLowerCase() !== "body") {
top += test.offsetTop;
test = test.offsetParent;
}
return top;
}
function viewPortHeight() {
var de = document.documentElement;
if(!!window.innerWidth)
{ return window.innerHeight; }
else if( de && !isNaN(de.clientHeight) )
{ return de.clientHeight; }
return 0;
}
function scrollY() {
if( window.pageYOffset ) { return window.pageYOffset; }
return Math.max(document.documentElement.scrollTop, document.body.scrollTop);
}
function checkvisible( elm ) {
var vpH = viewPortHeight(), // Viewport Height
st = scrollY(), // Scroll Top
y = posY(elm);
return (y > (vpH + st));
}
Using jQuery is a lot easier:
function checkVisible( elm, evalType ) {
evalType = evalType || "visible";
var vpH = $(window).height(), // Viewport Height
st = $(window).scrollTop(), // Scroll Top
y = $(elm).offset().top,
elementHeight = $(elm).height();
if (evalType === "visible") return ((y < (vpH + st)) && (y > (st - elementHeight)));
if (evalType === "above") return ((y < (vpH + st)));
}
This even offers a second parameter. With "visible" (or no second parameter) it strictly checks whether an element is on screen. If it is set to "above" it will return true when the element in question is on or above the screen.
See in action: http://jsfiddle.net/RJX5N/2/
I hope this answers your question.

Could you use jQuery, since it's cross-browser compatible?
function isOnScreen(element)
{
var curPos = element.offset();
var curTop = curPos.top;
var screenHeight = $(window).height();
return (curTop > screenHeight) ? false : true;
}
And then call the function using something like:
if(isOnScreen($('#myDivId'))) { /* Code here... */ };