Start jQuery animation when content in visible viewport [duplicate] - javascript
I'm loading elements via AJAX. Some of them are only visible if you scroll down the page. Is there any way I can know if an element is now in the visible part of the page?
This should do the trick:
function isScrolledIntoView(elem)
{
var docViewTop = $(window).scrollTop();
var docViewBottom = docViewTop + $(window).height();
var elemTop = $(elem).offset().top;
var elemBottom = elemTop + $(elem).height();
return ((elemBottom <= docViewBottom) && (elemTop >= docViewTop));
}
Simple Utility Function
This will allow you to call a utility function that accepts the element you're looking for and if you want the element to be fully in view or partially.
function Utils() {
}
Utils.prototype = {
constructor: Utils,
isElementInView: function (element, fullyInView) {
var pageTop = $(window).scrollTop();
var pageBottom = pageTop + $(window).height();
var elementTop = $(element).offset().top;
var elementBottom = elementTop + $(element).height();
if (fullyInView === true) {
return ((pageTop < elementTop) && (pageBottom > elementBottom));
} else {
return ((elementTop <= pageBottom) && (elementBottom >= pageTop));
}
}
};
var Utils = new Utils();
Usage
var isElementInView = Utils.isElementInView($('#flyout-left-container'), false);
if (isElementInView) {
console.log('in view');
} else {
console.log('out of view');
}
This answer in Vanilla:
function isScrolledIntoView(el) {
var rect = el.getBoundingClientRect();
var elemTop = rect.top;
var elemBottom = rect.bottom;
// Only completely visible elements return true:
var isVisible = (elemTop >= 0) && (elemBottom <= window.innerHeight);
// Partially visible elements return true:
//isVisible = elemTop < window.innerHeight && elemBottom >= 0;
return isVisible;
}
Using IntersectionObserver API
(native in modern browsers)
It's easy & efficient to determine if an element is visible in the viewport, or in any scrollable container, by using an observer.
The need to attach a scroll event and manually checking on the event callback is eliminated, which is more efficient:
// define an observer instance
var observer = new IntersectionObserver(onIntersection, {
root: null, // default is the viewport
threshold: .5 // percentage of target's visible area. Triggers "onIntersection"
})
// callback is called on intersection change
function onIntersection(entries, opts){
entries.forEach(entry =>
entry.target.classList.toggle('visible', entry.isIntersecting)
)
}
// Use the observer to observe an element
observer.observe( document.querySelector('.box') )
// To stop observing:
// observer.unobserve(entry.target)
span{ position:fixed; top:0; left:0; }
.box{ width:100px; height:100px; background:red; margin:1000px; transition:.75s; }
.box.visible{ background:green; border-radius:50%; }
<span>Scroll both Vertically & Horizontally...</span>
<div class='box'></div>
Supported by modern browsers, including mobile browsers. Not supported in IE - View browsers support table
Update: use IntersectionObserver
The best method I have found so far is the jQuery appear plugin. Works like a charm.
Mimics a custom "appear" event, which fires when an element scrolls into view or otherwise becomes visible to the user.
$('#foo').appear(function() {
$(this).text('Hello world');
});
This plugin can be used to prevent unnecessary requests for content that's hidden or outside the viewable area.
Here's my pure JavaScript solution that works if it's hidden inside a scrollable container too.
Demo here (try resizing the window too)
var visibleY = function(el){
var rect = el.getBoundingClientRect(), top = rect.top, height = rect.height,
el = el.parentNode
// Check if bottom of the element is off the page
if (rect.bottom < 0) return false
// Check its within the document viewport
if (top > document.documentElement.clientHeight) return false
do {
rect = el.getBoundingClientRect()
if (top <= rect.bottom === false) return false
// Check if the element is out of view due to a container scrolling
if ((top + height) <= rect.top) return false
el = el.parentNode
} while (el != document.body)
return true
};
EDIT 2016-03-26: I've updated the solution to account for scrolling past the element so it's hidden above the top of the scroll-able container.
EDIT 2018-10-08: Updated to handle when scrolled out of view above the screen.
Plain vanilla to check if element (el) is visible in scrollable div (holder)
function isElementVisible (el, holder) {
holder = holder || document.body
const { top, bottom, height } = el.getBoundingClientRect()
const holderRect = holder.getBoundingClientRect()
return top <= holderRect.top
? holderRect.top - top <= height
: bottom - holderRect.bottom <= height
}
Usage with jQuery:
var el = $('tr:last').get(0);
var holder = $('table').get(0);
var isVisible = isElementVisible(el, holder);
jQuery Waypoints plugin goes very nice here.
$('.entry').waypoint(function() {
alert('You have scrolled to an entry.');
});
There are some examples on the site of the plugin.
How about
function isInView(elem){
return $(elem).offset().top - $(window).scrollTop() < $(elem).height() ;
}
After that you can trigger whatever you want once the element is in view like this
$(window).scroll(function(){
if (isInView($('.classOfDivToCheck')))
//fire whatever you what
dothis();
})
That works for me just fine
Tweeked Scott Dowding's cool function for my requirement-
this is used for finding if the element has just scrolled into the screen i.e it's top edge .
function isScrolledIntoView(elem)
{
var docViewTop = $(window).scrollTop();
var docViewBottom = docViewTop + $(window).height();
var elemTop = $(elem).offset().top;
return ((elemTop <= docViewBottom) && (elemTop >= docViewTop));
}
WebResourcesDepot wrote a script to load while scrolling that uses jQuery some time ago. You can view their Live Demo Here. The beef of their functionality was this:
$(window).scroll(function(){
if ($(window).scrollTop() == $(document).height() - $(window).height()){
lastAddedLiveFunc();
}
});
function lastAddedLiveFunc() {
$('div#lastPostsLoader').html('<img src="images/bigLoader.gif">');
$.post("default.asp?action=getLastPosts&lastPostID="+$(".wrdLatest:last").attr("id"),
function(data){
if (data != "") {
$(".wrdLatest:last").after(data);
}
$('div#lastPostsLoader').empty();
});
};
Most answers here don't take into account that an element can also be hidden because it is scrolled out of view of a div, not only of the whole page.
To cover that possibility, you basically have to check if the element is positioned inside the bounds of each of its parents.
This solution does exactly that:
function(element, percentX, percentY){
var tolerance = 0.01; //needed because the rects returned by getBoundingClientRect provide the position up to 10 decimals
if(percentX == null){
percentX = 100;
}
if(percentY == null){
percentY = 100;
}
var elementRect = element.getBoundingClientRect();
var parentRects = [];
while(element.parentElement != null){
parentRects.push(element.parentElement.getBoundingClientRect());
element = element.parentElement;
}
var visibleInAllParents = parentRects.every(function(parentRect){
var visiblePixelX = Math.min(elementRect.right, parentRect.right) - Math.max(elementRect.left, parentRect.left);
var visiblePixelY = Math.min(elementRect.bottom, parentRect.bottom) - Math.max(elementRect.top, parentRect.top);
var visiblePercentageX = visiblePixelX / elementRect.width * 100;
var visiblePercentageY = visiblePixelY / elementRect.height * 100;
return visiblePercentageX + tolerance > percentX && visiblePercentageY + tolerance > percentY;
});
return visibleInAllParents;
};
It also lets you specify to what percentage it has to be visible in each direction.
It doesn't cover the possibility that it may be hidden due to other factors, like display: hidden.
This should work in all major browsers, since it only uses getBoundingClientRect. I personally tested it in Chrome and Internet Explorer 11.
isScrolledIntoView is a very needful function, so I tried it, it works for elements not heigher than the viewport, but if the element is bigger as the viewport it does not work. To fix this easily change the condition
return ((elemBottom <= docViewBottom) && (elemTop >= docViewTop));
to this:
return (docViewBottom >= elemTop && docViewTop <= elemBottom);
See demo here: http://jsfiddle.net/RRSmQ/
This considers any padding, border or margin the element has as well as elements larger than the viewport itself.
function inViewport($ele) {
var lBound = $(window).scrollTop(),
uBound = lBound + $(window).height(),
top = $ele.offset().top,
bottom = top + $ele.outerHeight(true);
return (top > lBound && top < uBound)
|| (bottom > lBound && bottom < uBound)
|| (lBound >= top && lBound <= bottom)
|| (uBound >= top && uBound <= bottom);
}
To call it use something like this:
var $myElement = $('#my-element'),
canUserSeeIt = inViewport($myElement);
console.log(canUserSeeIt); // true, if element is visible; false otherwise
Here is another solution:
<script type="text/javascript">
$.fn.is_on_screen = function(){
var win = $(window);
var viewport = {
top : win.scrollTop(),
left : win.scrollLeft()
};
viewport.right = viewport.left + win.width();
viewport.bottom = viewport.top + win.height();
var bounds = this.offset();
bounds.right = bounds.left + this.outerWidth();
bounds.bottom = bounds.top + this.outerHeight();
return (!(viewport.right < bounds.left || viewport.left > bounds.right || viewport.bottom < bounds.top || viewport.top > bounds.bottom));
};
if( $('.target').length > 0 ) { // if target element exists in DOM
if( $('.target').is_on_screen() ) { // if target element is visible on screen after DOM loaded
$('.log').html('<div class="alert alert-success">target element is visible on screen</div>'); // log info
} else {
$('.log').html('<div class="alert">target element is not visible on screen</div>'); // log info
}
}
$(window).on('scroll', function(){ // bind window scroll event
if( $('.target').length > 0 ) { // if target element exists in DOM
if( $('.target').is_on_screen() ) { // if target element is visible on screen after DOM loaded
$('.log').html('<div class="alert alert-success">target element is visible on screen</div>'); // log info
} else {
$('.log').html('<div class="alert">target element is not visible on screen</div>'); // log info
}
}
});
</script>
See it in JSFiddle
function isScrolledIntoView(elem) {
var docViewTop = $(window).scrollTop(),
docViewBottom = docViewTop + $(window).height(),
elemTop = $(elem).offset().top,
elemBottom = elemTop + $(elem).height();
//Is more than half of the element visible
return ((elemTop + ((elemBottom - elemTop)/2)) >= docViewTop && ((elemTop + ((elemBottom - elemTop)/2)) <= docViewBottom));
}
I needed to check visibility in elements inside scrollable DIV container
//p = DIV container scrollable
//e = element
function visible_in_container(p, e) {
var z = p.getBoundingClientRect();
var r = e.getBoundingClientRect();
// Check style visiblilty and off-limits
return e.style.opacity > 0 && e.style.display !== 'none' &&
e.style.visibility !== 'hidden' &&
!(r.top > z.bottom || r.bottom < z.top ||
r.left > z.right || r.right < z.left);
}
Building off of this great answer, you can simplify it a little further using ES2015+:
function isScrolledIntoView(el) {
const { top, bottom } = el.getBoundingClientRect()
return top >= 0 && bottom <= window.innerHeight
}
If you don't care about the top going out of the window and just care that the bottom has been viewed, this can be simplified to
function isSeen(el) {
return el.getBoundingClientRect().bottom <= window.innerHeight
}
or even the one-liner
const isSeen = el => el.getBoundingClientRect().bottom <= window.innerHeight
There is a plugin for jQuery called inview which adds a new "inview" event.
Here is some code for a jQuery plugin that doesn't use events:
$.extend($.expr[':'],{
inView: function(a) {
var st = (document.documentElement.scrollTop || document.body.scrollTop),
ot = $(a).offset().top,
wh = (window.innerHeight && window.innerHeight < $(window).height()) ? window.innerHeight : $(window).height();
return ot > st && ($(a).height() + ot) < (st + wh);
}
});
(function( $ ) {
$.fn.inView = function() {
var st = (document.documentElement.scrollTop || document.body.scrollTop),
ot = $(this).offset().top,
wh = (window.innerHeight && window.innerHeight < $(window).height()) ? window.innerHeight : $(window).height();
return ot > st && ($(this).height() + ot) < (st + wh);
};
})( jQuery );
I found this in a comment here ( http://remysharp.com/2009/01/26/element-in-view-event-plugin/ ) by a bloke called James
The easiest solution I found for this is Intersection Observer API:
var observer = new IntersectionObserver(function(entries) {
if(entries[0].isIntersecting === true)
console.log('Element has just become visible in screen');
}, { threshold: [0] });
observer.observe(document.querySelector("#main-container"));
I have such a method in my application, but it does not use jQuery:
/* Get the TOP position of a given element. */
function getPositionTop(element){
var offset = 0;
while(element) {
offset += element["offsetTop"];
element = element.offsetParent;
}
return offset;
}
/* Is a given element is visible or not? */
function isElementVisible(eltId) {
var elt = document.getElementById(eltId);
if (!elt) {
// Element not found.
return false;
}
// Get the top and bottom position of the given element.
var posTop = getPositionTop(elt);
var posBottom = posTop + elt.offsetHeight;
// Get the top and bottom position of the *visible* part of the window.
var visibleTop = document.body.scrollTop;
var visibleBottom = visibleTop + document.documentElement.offsetHeight;
return ((posBottom >= visibleTop) && (posTop <= visibleBottom));
}
Edit : This method works well for I.E. (at least version 6). Read the comments for compatibility with FF.
I prefer using jQuery expr
jQuery.extend(jQuery.expr[':'], {
inview: function (elem) {
var t = $(elem);
var offset = t.offset();
var win = $(window);
var winST = win.scrollTop();
var elHeight = t.outerHeight(true);
if ( offset.top > winST - elHeight && offset.top < winST + elHeight + win.height()) {
return true;
}
return false;
}
});
so you can use it this way
$(".my-elem:inview"); //returns only element that is in view
$(".my-elem").is(":inview"); //check if element is in view
$(".my-elem:inview").length; //check how many elements are in view
You can easly add such code inside scroll event function etc. to check it everytime user will scroll the view.
The Javascript code could be written as :
window.addEventListener('scroll', function() {
var element = document.querySelector('#main-container');
var position = element.getBoundingClientRect();
// checking whether fully visible
if(position.top >= 0 && position.bottom <= window.innerHeight) {
console.log('Element is fully visible in screen');
}
// checking for partial visibility
if(position.top < window.innerHeight && position.bottom >= 0) {
console.log('Element is partially visible in screen');
}
});
and in react js written as:
componentDidMount() {
window.addEventListener('scroll', this.isScrolledIntoView);
}
componentWillUnmount() {
window.removeEventListener('scroll', this.isScrolledIntoView);
}
isScrolledIntoView() {
var element = document.querySelector('.element');
var position = element.getBoundingClientRect();
// checking whether fully visible
if (position.top >= 0 && position.bottom <= window.innerHeight) {
console.log('Element is fully visible in screen');
}
// checking for partial visibility
if (position.top < window.innerHeight && position.bottom >= 0) {
console.log('Element is partially visible in screen');
}
}
If you want to tweak this for scrolling item within another div,
function isScrolledIntoView (elem, divID)
{
var docViewTop = $('#' + divID).scrollTop();
var docViewBottom = docViewTop + $('#' + divID).height();
var elemTop = $(elem).offset().top;
var elemBottom = elemTop + $(elem).height();
return ((elemBottom <= docViewBottom) && (elemTop >= docViewTop));
}
You can make use of jquery plugin "onScreen" to check if the element is in the current viewport when you scroll.
The plugin sets the ":onScreen" of the selector to true when the selector appears on the screen.
This is the link for the plugin which you can include in your project.
"http://benpickles.github.io/onScreen/jquery.onscreen.min.js"
You can try the below example which works for me.
$(document).scroll(function() {
if($("#div2").is(':onScreen')) {
console.log("Element appeared on Screen");
//do all your stuffs here when element is visible.
}
else {
console.log("Element not on Screen");
//do all your stuffs here when element is not visible.
}
});
HTML Code:
<div id="div1" style="width: 400px; height: 1000px; padding-top: 20px; position: relative; top: 45px"></div> <br>
<hr /> <br>
<div id="div2" style="width: 400px; height: 200px"></div>
CSS:
#div1 {
background-color: red;
}
#div2 {
background-color: green;
}
An example based off of this answer to check if an element is 75% visible (i.e. less than 25% of it is off of the screen).
function isScrolledIntoView(el) {
// check for 75% visible
var percentVisible = 0.75;
var elemTop = el.getBoundingClientRect().top;
var elemBottom = el.getBoundingClientRect().bottom;
var elemHeight = el.getBoundingClientRect().height;
var overhang = elemHeight * (1 - percentVisible);
var isVisible = (elemTop >= -overhang) && (elemBottom <= window.innerHeight + overhang);
return isVisible;
}
A more efficient version of this answer:
/**
* Is element within visible region of a scrollable container
* #param {HTMLElement} el - element to test
* #returns {boolean} true if within visible region, otherwise false
*/
function isScrolledIntoView(el) {
var rect = el.getBoundingClientRect();
return (rect.top >= 0) && (rect.bottom <= window.innerHeight);
}
Modified the accepted answer so that the element has to have it's display property set to something other than "none" to quality as visible.
function isScrolledIntoView(elem) {
var docViewTop = $(window).scrollTop();
var docViewBottom = docViewTop + $(window).height();
var elemTop = $(elem).offset().top;
var elemBottom = elemTop + $(elem).height();
var elemDisplayNotNone = $(elem).css("display") !== "none";
return ((elemBottom <= docViewBottom) && (elemTop >= docViewTop) && elemDisplayNotNone);
}
Here is a way to achieve the same thing using Mootools, in horizontal, vertical or both.
Element.implement({
inVerticalView: function (full) {
if (typeOf(full) === "null") {
full = true;
}
if (this.getStyle('display') === 'none') {
return false;
}
// Window Size and Scroll
var windowScroll = window.getScroll();
var windowSize = window.getSize();
// Element Size and Scroll
var elementPosition = this.getPosition();
var elementSize = this.getSize();
// Calculation Variables
var docViewTop = windowScroll.y;
var docViewBottom = docViewTop + windowSize.y;
var elemTop = elementPosition.y;
var elemBottom = elemTop + elementSize.y;
if (full) {
return ((elemBottom >= docViewTop) && (elemTop <= docViewBottom)
&& (elemBottom <= docViewBottom) && (elemTop >= docViewTop) );
} else {
return ((elemBottom <= docViewBottom) && (elemTop >= docViewTop));
}
},
inHorizontalView: function(full) {
if (typeOf(full) === "null") {
full = true;
}
if (this.getStyle('display') === 'none') {
return false;
}
// Window Size and Scroll
var windowScroll = window.getScroll();
var windowSize = window.getSize();
// Element Size and Scroll
var elementPosition = this.getPosition();
var elementSize = this.getSize();
// Calculation Variables
var docViewLeft = windowScroll.x;
var docViewRight = docViewLeft + windowSize.x;
var elemLeft = elementPosition.x;
var elemRight = elemLeft + elementSize.x;
if (full) {
return ((elemRight >= docViewLeft) && (elemLeft <= docViewRight)
&& (elemRight <= docViewRight) && (elemLeft >= docViewLeft) );
} else {
return ((elemRight <= docViewRight) && (elemLeft >= docViewLeft));
}
},
inView: function(full) {
return this.inHorizontalView(full) && this.inVerticalView(full);
}});
This method will return true if any part of the element is visible on the page. It worked better in my case and may help someone else.
function isOnScreen(element) {
var elementOffsetTop = element.offset().top;
var elementHeight = element.height();
var screenScrollTop = $(window).scrollTop();
var screenHeight = $(window).height();
var scrollIsAboveElement = elementOffsetTop + elementHeight - screenScrollTop >= 0;
var elementIsVisibleOnScreen = screenScrollTop + screenHeight - elementOffsetTop >= 0;
return scrollIsAboveElement && elementIsVisibleOnScreen;
}
There are over 30 answers to this question, and none of them use the amazingly simple, pure JS solution that I have been using. There is no need to load jQuery just to solve this, as many others are pushing.
In order to tell if the element is within the viewport, we must first determine the elements position within the body. We do not need to do this recursively as I once thought. Instead, we can use element.getBoundingClientRect().
pos = elem.getBoundingClientRect().top - document.body.getBoundingClientRect().top;
This value is the Y difference between the top of the object and the top of the body.
We then must tell if the element is within view. Most implementations ask if the full element is within the viewport, so this is what we shall cover.
First of all, the top position of the window is: window.scrollY.
We can get the bottom position of the window by adding the window's height to its top position:
var window_bottom_position = window.scrollY + window.innerHeight;
Lets create a simple function for getting the element's top position:
function getElementWindowTop(elem){
return elem && typeof elem.getBoundingClientRect === 'function' ? elem.getBoundingClientRect().top - document.body.getBoundingClientRect().top : 0;
}
This function will return the element's top position within the window or it will return 0 if you pass it something other than an element with the .getBoundingClientRect() method. This method has been around for a long time, so you shouldn't have to worry about your browser not supporting it.
Now, our element's top position is:
var element_top_position = getElementWindowTop(element);
And or element's bottom position is:
var element_bottom_position = element_top_position + element.clientHeight;
Now we can determine if the element is within the viewport by checking if the element's bottom position is lower than the viewport's top position and by checking if the element's top position is higher than the viewport's bottom position:
if(element_bottom_position >= window.scrollY
&& element_top_position <= window_bottom_position){
//element is in view
else
//element is not in view
From there, you can perform the logic to add or remove an in-view class on your element, which you can then handle later with transition effects in your CSS.
I am absolutely amazed that I did not find this solution anywhere else, but I do believe that this is the cleanest and most effective solution, and it doesn't require you to load jQuery!
Related
I need to add an 'active' class to sections using addEventListener when the user scrolls to new section [duplicate]
Is there an efficient way to tell if a DOM element (in an HTML document) is currently visible (appears in the viewport)? (The question refers to Firefox.)
Now most browsers support getBoundingClientRect method, which has become the best practice. Using an old answer is very slow, not accurate and has several bugs.
The solution selected as correct is almost never precise.
This solution was tested on Internet Explorer 7 (and later), iOS 5 (and later) Safari, Android 2.0 (Eclair) and later, BlackBerry, Opera Mobile, and Internet Explorer Mobile 9.
function isElementInViewport (el) {
// Special bonus for those using jQuery
if (typeof jQuery === "function" && el instanceof jQuery) {
el = el[0];
}
var rect = el.getBoundingClientRect();
return (
rect.top >= 0 &&
rect.left >= 0 &&
rect.bottom <= (window.innerHeight || document.documentElement.clientHeight) && /* or $(window).height() */
rect.right <= (window.innerWidth || document.documentElement.clientWidth) /* or $(window).width() */
);
}
How to use:
You can be sure that the function given above returns correct answer at the moment of time when it is called, but what about tracking element's visibility as an event?
Place the following code at the bottom of your <body> tag:
function onVisibilityChange(el, callback) {
var old_visible;
return function () {
var visible = isElementInViewport(el);
if (visible != old_visible) {
old_visible = visible;
if (typeof callback == 'function') {
callback();
}
}
}
}
var handler = onVisibilityChange(el, function() {
/* Your code go here */
});
// jQuery
$(window).on('DOMContentLoaded load resize scroll', handler);
/* // Non-jQuery
if (window.addEventListener) {
addEventListener('DOMContentLoaded', handler, false);
addEventListener('load', handler, false);
addEventListener('scroll', handler, false);
addEventListener('resize', handler, false);
} else if (window.attachEvent) {
attachEvent('onDOMContentLoaded', handler); // Internet Explorer 9+ :(
attachEvent('onload', handler);
attachEvent('onscroll', handler);
attachEvent('onresize', handler);
}
*/
If you do any DOM modifications, they can change your element's visibility of course.
Guidelines and common pitfalls:
Maybe you need to track page zoom / mobile device pinch? jQuery should handle zoom/pinch cross browser, otherwise first or second link should help you.
If you modify DOM, it can affect the element's visibility. You should take control over that and call handler() manually. Unfortunately, we don't have any cross browser onrepaint event. On the other hand that allows us to make optimizations and perform re-check only on DOM modifications that can change an element's visibility.
Never Ever use it inside jQuery $(document).ready() only, because there is no warranty CSS has been applied in this moment. Your code can work locally with your CSS on a hard drive, but once put on a remote server it will fail.
After DOMContentLoaded is fired, styles are applied, but the images are not loaded yet. So, we should add window.onload event listener.
We can't catch zoom/pinch event yet.
The last resort could be the following code:
/* TODO: this looks like a very bad code */
setInterval(handler, 600);
You can use the awesome feature pageVisibiliy of the HTML5 API if you care if the tab with your web page is active and visible.
TODO: this method does not handle two situations:
Overlapping using z-index.
Using overflow-scroll in element's container.
Try something new - The Intersection Observer API explained.
Update: Time marches on and so have our browsers. This technique is no longer recommended and you should use Dan's solution if you do not need to support version of Internet Explorer before 7.
Original solution (now outdated):
This will check if the element is entirely visible in the current viewport:
function elementInViewport(el) {
var top = el.offsetTop;
var left = el.offsetLeft;
var width = el.offsetWidth;
var height = el.offsetHeight;
while(el.offsetParent) {
el = el.offsetParent;
top += el.offsetTop;
left += el.offsetLeft;
}
return (
top >= window.pageYOffset &&
left >= window.pageXOffset &&
(top + height) <= (window.pageYOffset + window.innerHeight) &&
(left + width) <= (window.pageXOffset + window.innerWidth)
);
}
You could modify this simply to determine if any part of the element is visible in the viewport:
function elementInViewport2(el) {
var top = el.offsetTop;
var left = el.offsetLeft;
var width = el.offsetWidth;
var height = el.offsetHeight;
while(el.offsetParent) {
el = el.offsetParent;
top += el.offsetTop;
left += el.offsetLeft;
}
return (
top < (window.pageYOffset + window.innerHeight) &&
left < (window.pageXOffset + window.innerWidth) &&
(top + height) > window.pageYOffset &&
(left + width) > window.pageXOffset
);
}
Update
In modern browsers, you might want to check out the Intersection Observer API which provides the following benefits:
Better performance than listening for scroll events
Works in cross domain iframes
Can tell if an element is obstructing/intersecting another
Intersection Observer is on its way to being a full-fledged standard and is already supported in Chrome 51+, Edge 15+ and Firefox 55+ and is under development for Safari. There's also a polyfill available.
Previous answer
There are some issues with the answer provided by Dan that might make it an unsuitable approach for some situations. Some of these issues are pointed out in his answer near the bottom, that his code will give false positives for elements that are:
Hidden by another element in front of the one being tested
Outside the visible area of a parent or ancestor element
An element or its children hidden by using the CSS clip property
These limitations are demonstrated in the following results of a simple test:
The solution: isElementVisible()
Here's a solution to those problems, with the test result below and an explanation of some parts of the code.
function isElementVisible(el) {
var rect = el.getBoundingClientRect(),
vWidth = window.innerWidth || document.documentElement.clientWidth,
vHeight = window.innerHeight || document.documentElement.clientHeight,
efp = function (x, y) { return document.elementFromPoint(x, y) };
// Return false if it's not in the viewport
if (rect.right < 0 || rect.bottom < 0
|| rect.left > vWidth || rect.top > vHeight)
return false;
// Return true if any of its four corners are visible
return (
el.contains(efp(rect.left, rect.top))
|| el.contains(efp(rect.right, rect.top))
|| el.contains(efp(rect.right, rect.bottom))
|| el.contains(efp(rect.left, rect.bottom))
);
}
Passing test: http://jsfiddle.net/AndyE/cAY8c/
And the result:
Additional notes
This method is not without its own limitations, however. For instance, an element being tested with a lower z-index than another element at the same location would be identified as hidden even if the element in front doesn't actually hide any part of it. Still, this method has its uses in some cases that Dan's solution doesn't cover.
Both element.getBoundingClientRect() and document.elementFromPoint() are part of the CSSOM Working Draft specification and are supported in at least IE 6 and later and most desktop browsers for a long time (albeit, not perfectly). See Quirksmode on these functions for more information.
contains() is used to see if the element returned by document.elementFromPoint() is a child node of the element we're testing for visibility. It also returns true if the element returned is the same element. This just makes the check more robust. It's supported in all major browsers, Firefox 9.0 being the last of them to add it. For older Firefox support, check this answer's history.
If you want to test more points around the element for visibility―ie, to make sure the element isn't covered by more than, say, 50%―it wouldn't take much to adjust the last part of the answer. However, be aware that it would probably be very slow if you checked every pixel to make sure it was 100% visible.
I tried Dan's answer, however, the algebra used to determine the bounds means that the element must be both ≤ the viewport size and completely inside the viewport to get true, easily leading to false negatives. If you want to determine whether an element is in the viewport at all, ryanve's answer is close but the element being tested should overlap the viewport, so try this:
function isElementInViewport(el) {
var rect = el.getBoundingClientRect();
return rect.bottom > 0 &&
rect.right > 0 &&
rect.left < (window.innerWidth || document.documentElement.clientWidth) /* or $(window).width() */ &&
rect.top < (window.innerHeight || document.documentElement.clientHeight) /* or $(window).height() */;
}
We have now a native javascript Intersection Observer API
from which we can detect elements either they are in the viewport or not.
Here is example
const el = document.querySelector('#el')
const observer = new window.IntersectionObserver(([entry]) => {
if (entry.isIntersecting) {
console.log('ENTER')
return
}
console.log('LEAVE')
}, {
root: null,
threshold: 0.1, // set offset 0.1 means trigger if atleast 10% of element in viewport
})
observer.observe(el);
body {
height: 300vh;
}
#el {
margin-top: 100vh;
}
<div id="el">this is element</div>
See the source of verge, which uses getBoundingClientRect. It's like:
function inViewport (element) {
if (!element) return false;
if (1 !== element.nodeType) return false;
var html = document.documentElement;
var rect = element.getBoundingClientRect();
return !!rect &&
rect.bottom >= 0 &&
rect.right >= 0 &&
rect.left <= html.clientWidth &&
rect.top <= html.clientHeight;
}
It returns true if any part of the element is in the viewport.
As a public service:
Dan's answer with the correct calculations (element can be > window, especially on mobile phone screens), and correct jQuery testing, as well as adding isElementPartiallyInViewport:
By the way, the difference between window.innerWidth and document.documentElement.clientWidth is that clientWidth/clientHeight doesn't include the scrollbar, while window.innerWidth/Height does.
function isElementPartiallyInViewport(el)
{
// Special bonus for those using jQuery
if (typeof jQuery !== 'undefined' && el instanceof jQuery)
el = el[0];
var rect = el.getBoundingClientRect();
// DOMRect { x: 8, y: 8, width: 100, height: 100, top: 8, right: 108, bottom: 108, left: 8 }
var windowHeight = (window.innerHeight || document.documentElement.clientHeight);
var windowWidth = (window.innerWidth || document.documentElement.clientWidth);
// http://stackoverflow.com/questions/325933/determine-whether-two-date-ranges-overlap
var vertInView = (rect.top <= windowHeight) && ((rect.top + rect.height) >= 0);
var horInView = (rect.left <= windowWidth) && ((rect.left + rect.width) >= 0);
return (vertInView && horInView);
}
// http://stackoverflow.com/questions/123999/how-to-tell-if-a-dom-element-is-visible-in-the-current-viewport
function isElementInViewport (el)
{
// Special bonus for those using jQuery
if (typeof jQuery !== 'undefined' && el instanceof jQuery)
el = el[0];
var rect = el.getBoundingClientRect();
var windowHeight = (window.innerHeight || document.documentElement.clientHeight);
var windowWidth = (window.innerWidth || document.documentElement.clientWidth);
return (
(rect.left >= 0)
&& (rect.top >= 0)
&& ((rect.left + rect.width) <= windowWidth)
&& ((rect.top + rect.height) <= windowHeight)
);
}
function fnIsVis(ele)
{
var inVpFull = isElementInViewport(ele);
var inVpPartial = isElementPartiallyInViewport(ele);
console.clear();
console.log("Fully in viewport: " + inVpFull);
console.log("Partially in viewport: " + inVpPartial);
}
Test-case
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta name="description" content="">
<meta name="author" content="">
<title>Test</title>
<!--
<script src="http://cdnjs.cloudflare.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script src="scrollMonitor.js"></script>
-->
<script type="text/javascript">
function isElementPartiallyInViewport(el)
{
// Special bonus for those using jQuery
if (typeof jQuery !== 'undefined' && el instanceof jQuery)
el = el[0];
var rect = el.getBoundingClientRect();
// DOMRect { x: 8, y: 8, width: 100, height: 100, top: 8, right: 108, bottom: 108, left: 8 }
var windowHeight = (window.innerHeight || document.documentElement.clientHeight);
var windowWidth = (window.innerWidth || document.documentElement.clientWidth);
// http://stackoverflow.com/questions/325933/determine-whether-two-date-ranges-overlap
var vertInView = (rect.top <= windowHeight) && ((rect.top + rect.height) >= 0);
var horInView = (rect.left <= windowWidth) && ((rect.left + rect.width) >= 0);
return (vertInView && horInView);
}
// http://stackoverflow.com/questions/123999/how-to-tell-if-a-dom-element-is-visible-in-the-current-viewport
function isElementInViewport (el)
{
// Special bonus for those using jQuery
if (typeof jQuery !== 'undefined' && el instanceof jQuery)
el = el[0];
var rect = el.getBoundingClientRect();
var windowHeight = (window.innerHeight || document.documentElement.clientHeight);
var windowWidth = (window.innerWidth || document.documentElement.clientWidth);
return (
(rect.left >= 0)
&& (rect.top >= 0)
&& ((rect.left + rect.width) <= windowWidth)
&& ((rect.top + rect.height) <= windowHeight)
);
}
function fnIsVis(ele)
{
var inVpFull = isElementInViewport(ele);
var inVpPartial = isElementPartiallyInViewport(ele);
console.clear();
console.log("Fully in viewport: " + inVpFull);
console.log("Partially in viewport: " + inVpPartial);
}
// var scrollLeft = (window.pageXOffset !== undefined) ? window.pageXOffset : (document.documentElement || document.body.parentNode || document.body).scrollLeft,
// var scrollTop = (window.pageYOffset !== undefined) ? window.pageYOffset : (document.documentElement || document.body.parentNode || document.body).scrollTop;
</script>
</head>
<body>
<div style="display: block; width: 2000px; height: 10000px; background-color: green;">
<br /><br /><br /><br /><br /><br />
<br /><br /><br /><br /><br /><br />
<br /><br /><br /><br /><br /><br />
<input type="button" onclick="fnIsVis(document.getElementById('myele'));" value="det" />
<br /><br /><br /><br /><br /><br />
<br /><br /><br /><br /><br /><br />
<br /><br /><br /><br /><br /><br />
<div style="background-color: crimson; display: inline-block; width: 800px; height: 500px;" ></div>
<div id="myele" onclick="fnIsVis(this);" style="display: inline-block; width: 100px; height: 100px; background-color: hotpink;">
t
</div>
<br /><br /><br /><br /><br /><br />
<br /><br /><br /><br /><br /><br />
<br /><br /><br /><br /><br /><br />
<input type="button" onclick="fnIsVis(document.getElementById('myele'));" value="det" />
</div>
<!--
<script type="text/javascript">
var element = document.getElementById("myele");
var watcher = scrollMonitor.create(element);
watcher.lock();
watcher.stateChange(function() {
console.log("state changed");
// $(element).toggleClass('fixed', this.isAboveViewport)
});
</script>
-->
</body>
</html>
My shorter and faster version:
function isElementOutViewport(el){
var rect = el.getBoundingClientRect();
return rect.bottom < 0 || rect.right < 0 || rect.left > window.innerWidth || rect.top > window.innerHeight;
}
And a jsFiddle as required: https://jsfiddle.net/on1g619L/1/
The new Intersection Observer API addresses this question very directly.
This solution will need a polyfill as Safari, Opera and Internet Explorer don't support this yet (the polyfill is included in the solution).
In this solution, there is a box out of view that is the target (observed). When it comes into view, the button at the top in the header is hidden. It is shown once the box leaves the view.
const buttonToHide = document.querySelector('button');
const hideWhenBoxInView = new IntersectionObserver((entries) => {
if (entries[0].intersectionRatio <= 0) { // If not in view
buttonToHide.style.display = "inherit";
} else {
buttonToHide.style.display = "none";
}
});
hideWhenBoxInView.observe(document.getElementById('box'));
header {
position: fixed;
top: 0;
width: 100vw;
height: 30px;
background-color: lightgreen;
}
.wrapper {
position: relative;
margin-top: 600px;
}
#box {
position: relative;
left: 175px;
width: 150px;
height: 135px;
background-color: lightblue;
border: 2px solid;
}
<script src="https://polyfill.io/v2/polyfill.min.js?features=IntersectionObserver"></script>
<header>
<button>NAVIGATION BUTTON TO HIDE</button>
</header>
<div class="wrapper">
<div id="box">
</div>
</div>
I found it troubling that there wasn't a jQuery-centric version of the functionality available. When I came across Dan's solution I spied the opportunity to provide something for folks who like to program in the jQuery OO style. It's nice and snappy and works like a charm for me.
Bada bing bada boom
$.fn.inView = function(){
if(!this.length)
return false;
var rect = this.get(0).getBoundingClientRect();
return (
rect.top >= 0 &&
rect.left >= 0 &&
rect.bottom <= (window.innerHeight || document.documentElement.clientHeight) &&
rect.right <= (window.innerWidth || document.documentElement.clientWidth)
);
};
// Additional examples for other use cases
// Is true false whether an array of elements are all in view
$.fn.allInView = function(){
var all = [];
this.forEach(function(){
all.push( $(this).inView() );
});
return all.indexOf(false) === -1;
};
// Only the class elements in view
$('.some-class').filter(function(){
return $(this).inView();
});
// Only the class elements not in view
$('.some-class').filter(function(){
return !$(this).inView();
});
Usage
$(window).on('scroll',function(){
if( $('footer').inView() ) {
// Do cool stuff
}
});
The simplest solution as the support of Element.getBoundingClientRect() has become perfect:
function isInView(el) {
const box = el.getBoundingClientRect();
return box.top < window.innerHeight && box.bottom >= 0;
}
All answers I've encountered here only check if the element is positioned inside the current viewport. But that doesn't mean that it is visible.
What if the given element is inside a div with overflowing content, and it is scrolled out of view?
To solve that, you'd have to check if the element is contained by all parents.
My solution does exactly that:
It also allows you to specify how much of the element has to be visible.
Element.prototype.isVisible = function(percentX, percentY){
var tolerance = 0.01; //needed because the rects returned by getBoundingClientRect provide the position up to 10 decimals
if(percentX == null){
percentX = 100;
}
if(percentY == null){
percentY = 100;
}
var elementRect = this.getBoundingClientRect();
var parentRects = [];
var element = this;
while(element.parentElement != null){
parentRects.push(element.parentElement.getBoundingClientRect());
element = element.parentElement;
}
var visibleInAllParents = parentRects.every(function(parentRect){
var visiblePixelX = Math.min(elementRect.right, parentRect.right) - Math.max(elementRect.left, parentRect.left);
var visiblePixelY = Math.min(elementRect.bottom, parentRect.bottom) - Math.max(elementRect.top, parentRect.top);
var visiblePercentageX = visiblePixelX / elementRect.width * 100;
var visiblePercentageY = visiblePixelY / elementRect.height * 100;
return visiblePercentageX + tolerance > percentX && visiblePercentageY + tolerance > percentY;
});
return visibleInAllParents;
};
This solution ignored the fact that elements may not be visible due to other facts, like opacity: 0.
I have tested this solution in Chrome and Internet Explorer 11.
I find that the accepted answer here is overly complicated for most use cases. This code does the job well (using jQuery) and differentiates between fully visible and partially visible elements:
var element = $("#element");
var topOfElement = element.offset().top;
var bottomOfElement = element.offset().top + element.outerHeight(true);
var $window = $(window);
$window.bind('scroll', function() {
var scrollTopPosition = $window.scrollTop()+$window.height();
var windowScrollTop = $window.scrollTop()
if (windowScrollTop > topOfElement && windowScrollTop < bottomOfElement) {
// Element is partially visible (above viewable area)
console.log("Element is partially visible (above viewable area)");
} else if (windowScrollTop > bottomOfElement && windowScrollTop > topOfElement) {
// Element is hidden (above viewable area)
console.log("Element is hidden (above viewable area)");
} else if (scrollTopPosition < topOfElement && scrollTopPosition < bottomOfElement) {
// Element is hidden (below viewable area)
console.log("Element is hidden (below viewable area)");
} else if (scrollTopPosition < bottomOfElement && scrollTopPosition > topOfElement) {
// Element is partially visible (below viewable area)
console.log("Element is partially visible (below viewable area)");
} else {
// Element is completely visible
console.log("Element is completely visible");
}
});
Here's my solution. It will work if an element is hidden inside a scrollable container.
Here's a demo (try re-sizing the window to)
var visibleY = function(el){
var top = el.getBoundingClientRect().top, rect, el = el.parentNode;
do {
rect = el.getBoundingClientRect();
if (top <= rect.bottom === false)
return false;
el = el.parentNode;
} while (el != document.body);
// Check it's within the document viewport
return top <= document.documentElement.clientHeight;
};
I only needed to check if it's visible in the Y axis (for a scrolling Ajax load-more-records feature).
I think this is a more functional way to do it.
Dan's answer do not work in a recursive context.
This function solves the problem when your element is inside others scrollable divs by testing any levels recursively up to the HTML tag, and stops at the first false.
/**
* fullVisible=true only returns true if the all object rect is visible
*/
function isReallyVisible(el, fullVisible) {
if ( el.tagName == "HTML" )
return true;
var parentRect=el.parentNode.getBoundingClientRect();
var rect = arguments[2] || el.getBoundingClientRect();
return (
( fullVisible ? rect.top >= parentRect.top : rect.bottom > parentRect.top ) &&
( fullVisible ? rect.left >= parentRect.left : rect.right > parentRect.left ) &&
( fullVisible ? rect.bottom <= parentRect.bottom : rect.top < parentRect.bottom ) &&
( fullVisible ? rect.right <= parentRect.right : rect.left < parentRect.right ) &&
isReallyVisible(el.parentNode, fullVisible, rect)
);
};
The most accepted answers don't work when zooming in Google Chrome on Android. In combination with Dan's answer, to account for Chrome on Android, visualViewport must be used. The following example only takes the vertical check into account and uses jQuery for the window height:
var Rect = YOUR_ELEMENT.getBoundingClientRect();
var ElTop = Rect.top, ElBottom = Rect.bottom;
var WindowHeight = $(window).height();
if(window.visualViewport) {
ElTop -= window.visualViewport.offsetTop;
ElBottom -= window.visualViewport.offsetTop;
WindowHeight = window.visualViewport.height;
}
var WithinScreen = (ElTop >= 0 && ElBottom <= WindowHeight);
/**
* Returns Element placement information in Viewport
* #link https://stackoverflow.com/a/70476497/2453148
*
* #typedef {object} ViewportInfo - Whether the element is…
* #property {boolean} isInViewport - fully or partially in the viewport
* #property {boolean} isPartiallyInViewport - partially in the viewport
* #property {boolean} isInsideViewport - fully inside viewport
* #property {boolean} isAroundViewport - completely covers the viewport
* #property {boolean} isOnEdge - intersects the edge of viewport
* #property {boolean} isOnTopEdge - intersects the top edge
* #property {boolean} isOnRightEdge - intersects the right edge
* #property {boolean} isOnBottomEdge - is intersects the bottom edge
* #property {boolean} isOnLeftEdge - is intersects the left edge
*
* #param el Element
* #return {Object} ViewportInfo
*/
function getElementViewportInfo(el) {
let result = {};
let rect = el.getBoundingClientRect();
let windowHeight = window.innerHeight || document.documentElement.clientHeight;
let windowWidth = window.innerWidth || document.documentElement.clientWidth;
let insideX = rect.left >= 0 && rect.left + rect.width <= windowWidth;
let insideY = rect.top >= 0 && rect.top + rect.height <= windowHeight;
result.isInsideViewport = insideX && insideY;
let aroundX = rect.left < 0 && rect.left + rect.width > windowWidth;
let aroundY = rect.top < 0 && rect.top + rect.height > windowHeight;
result.isAroundViewport = aroundX && aroundY;
let onTop = rect.top < 0 && rect.top + rect.height > 0;
let onRight = rect.left < windowWidth && rect.left + rect.width > windowWidth;
let onLeft = rect.left < 0 && rect.left + rect.width > 0;
let onBottom = rect.top < windowHeight && rect.top + rect.height > windowHeight;
let onY = insideY || aroundY || onTop || onBottom;
let onX = insideX || aroundX || onLeft || onRight;
result.isOnTopEdge = onTop && onX;
result.isOnRightEdge = onRight && onY;
result.isOnBottomEdge = onBottom && onX;
result.isOnLeftEdge = onLeft && onY;
result.isOnEdge = result.isOnLeftEdge || result.isOnRightEdge ||
result.isOnTopEdge || result.isOnBottomEdge;
let isInX =
insideX || aroundX || result.isOnLeftEdge || result.isOnRightEdge;
let isInY =
insideY || aroundY || result.isOnTopEdge || result.isOnBottomEdge;
result.isInViewport = isInX && isInY;
result.isPartiallyInViewport =
result.isInViewport && result.isOnEdge;
return result;
}
Based on dan's solution, I had a go at cleaning up the implementation so that using it multiple times on the same page is easier:
$(function() {
$(window).on('load resize scroll', function() {
addClassToElementInViewport($('.bug-icon'), 'animate-bug-icon');
addClassToElementInViewport($('.another-thing'), 'animate-thing');
// 👏 repeat as needed ...
});
function addClassToElementInViewport(element, newClass) {
if (inViewport(element)) {
element.addClass(newClass);
}
}
function inViewport(element) {
if (typeof jQuery === "function" && element instanceof jQuery) {
element = element[0];
}
var elementBounds = element.getBoundingClientRect();
return (
elementBounds.top >= 0 &&
elementBounds.left >= 0 &&
elementBounds.bottom <= $(window).height() &&
elementBounds.right <= $(window).width()
);
}
});
The way I'm using it is that when the element scrolls into view, I'm adding a class that triggers a CSS keyframe animation. It's pretty straightforward and works especially well when you've got like 10+ things to conditionally animate on a page.
Most of the usages in previous answers are failing at these points:
-When any pixel of an element is visible, but not "a corner",
-When an element is bigger than viewport and centered,
-Most of them are checking only for a singular element inside a document or window.
Well, for all these problems I've a solution and the plus sides are:
-You can return visible when only a pixel from any sides shows up and is not a corner,
-You can still return visible while element bigger than viewport,
-You can choose your parent element or you can automatically let it choose,
-Works on dynamically added elements too.
If you check the snippets below you will see the difference in using overflow-scroll in element's container will not cause any trouble and see that unlike other answers here even if a pixel shows up from any side or when an element is bigger than viewport and we are seeing inner pixels of the element it still works.
Usage is simple:
// For checking element visibility from any sides
isVisible(element)
// For checking elements visibility in a parent you would like to check
var parent = document; // Assuming you check if 'element' inside 'document'
isVisible(element, parent)
// For checking elements visibility even if it's bigger than viewport
isVisible(element, null, true) // Without parent choice
isVisible(element, parent, true) // With parent choice
A demonstration without crossSearchAlgorithm which is usefull for elements bigger than viewport check element3 inner pixels to see:
function isVisible(element, parent, crossSearchAlgorithm) {
var rect = element.getBoundingClientRect(),
prect = (parent != undefined) ? parent.getBoundingClientRect() : element.parentNode.getBoundingClientRect(),
csa = (crossSearchAlgorithm != undefined) ? crossSearchAlgorithm : false,
efp = function (x, y) { return document.elementFromPoint(x, y) };
// Return false if it's not in the viewport
if (rect.right < prect.left || rect.bottom < prect.top || rect.left > prect.right || rect.top > prect.bottom) {
return false;
}
var flag = false;
// Return true if left to right any border pixel reached
for (var x = rect.left; x < rect.right; x++) {
if (element.contains(efp(rect.top, x)) || element.contains(efp(rect.bottom, x))) {
flag = true;
break;
}
}
// Return true if top to bottom any border pixel reached
if (flag == false) {
for (var y = rect.top; y < rect.bottom; y++) {
if (element.contains(efp(rect.left, y)) || element.contains(efp(rect.right, y))) {
flag = true;
break;
}
}
}
if(csa) {
// Another algorithm to check if element is centered and bigger than viewport
if (flag == false) {
var x = rect.left;
var y = rect.top;
// From top left to bottom right
while(x < rect.right || y < rect.bottom) {
if (element.contains(efp(x,y))) {
flag = true;
break;
}
if(x < rect.right) { x++; }
if(y < rect.bottom) { y++; }
}
if (flag == false) {
x = rect.right;
y = rect.top;
// From top right to bottom left
while(x > rect.left || y < rect.bottom) {
if (element.contains(efp(x,y))) {
flag = true;
break;
}
if(x > rect.left) { x--; }
if(y < rect.bottom) { y++; }
}
}
}
}
return flag;
}
// Check multiple elements visibility
document.getElementById('container').addEventListener("scroll", function() {
var elementList = document.getElementsByClassName("element");
var console = document.getElementById('console');
for (var i=0; i < elementList.length; i++) {
// I did not define parent, so it will be element's parent
if (isVisible(elementList[i])) {
console.innerHTML = "Element with id[" + elementList[i].id + "] is visible!";
break;
} else {
console.innerHTML = "Element with id[" + elementList[i].id + "] is hidden!";
}
}
});
// Dynamically added elements
for(var i=4; i <= 6; i++) {
var newElement = document.createElement("div");
newElement.id = "element" + i;
newElement.classList.add("element");
document.getElementById('container').appendChild(newElement);
}
#console { background-color: yellow; }
#container {
width: 300px;
height: 100px;
background-color: lightblue;
overflow-y: auto;
padding-top: 150px;
margin: 45px;
}
.element {
margin: 400px;
width: 400px;
height: 320px;
background-color: green;
}
#element3 {
position: relative;
margin: 40px;
width: 720px;
height: 520px;
background-color: green;
}
#element3::before {
content: "";
position: absolute;
top: -10px;
left: -10px;
margin: 0px;
width: 740px;
height: 540px;
border: 5px dotted green;
background: transparent;
}
<div id="console"></div>
<div id="container">
<div id="element1" class="element"></div>
<div id="element2" class="element"></div>
<div id="element3" class="element"></div>
</div>
You see, when you are inside the element3 it fails to tell if it's visible or not, because we are only checking if the element is visible from sides or corners.
And this one includes crossSearchAlgorithm which allows you to still return visible when the element is bigger than the viewport:
function isVisible(element, parent, crossSearchAlgorithm) {
var rect = element.getBoundingClientRect(),
prect = (parent != undefined) ? parent.getBoundingClientRect() : element.parentNode.getBoundingClientRect(),
csa = (crossSearchAlgorithm != undefined) ? crossSearchAlgorithm : false,
efp = function (x, y) { return document.elementFromPoint(x, y) };
// Return false if it's not in the viewport
if (rect.right < prect.left || rect.bottom < prect.top || rect.left > prect.right || rect.top > prect.bottom) {
return false;
}
var flag = false;
// Return true if left to right any border pixel reached
for (var x = rect.left; x < rect.right; x++) {
if (element.contains(efp(rect.top, x)) || element.contains(efp(rect.bottom, x))) {
flag = true;
break;
}
}
// Return true if top to bottom any border pixel reached
if (flag == false) {
for (var y = rect.top; y < rect.bottom; y++) {
if (element.contains(efp(rect.left, y)) || element.contains(efp(rect.right, y))) {
flag = true;
break;
}
}
}
if(csa) {
// Another algorithm to check if element is centered and bigger than viewport
if (flag == false) {
var x = rect.left;
var y = rect.top;
// From top left to bottom right
while(x < rect.right || y < rect.bottom) {
if (element.contains(efp(x,y))) {
flag = true;
break;
}
if(x < rect.right) { x++; }
if(y < rect.bottom) { y++; }
}
if (flag == false) {
x = rect.right;
y = rect.top;
// From top right to bottom left
while(x > rect.left || y < rect.bottom) {
if (element.contains(efp(x,y))) {
flag = true;
break;
}
if(x > rect.left) { x--; }
if(y < rect.bottom) { y++; }
}
}
}
}
return flag;
}
// Check multiple elements visibility
document.getElementById('container').addEventListener("scroll", function() {
var elementList = document.getElementsByClassName("element");
var console = document.getElementById('console');
for (var i=0; i < elementList.length; i++) {
// I did not define parent so it will be element's parent
// and it will do crossSearchAlgorithm
if (isVisible(elementList[i],null,true)) {
console.innerHTML = "Element with id[" + elementList[i].id + "] is visible!";
break;
} else {
console.innerHTML = "Element with id[" + elementList[i].id + "] is hidden!";
}
}
});
// Dynamically added elements
for(var i=4; i <= 6; i++) {
var newElement = document.createElement("div");
newElement.id = "element" + i;
newElement.classList.add("element");
document.getElementById('container').appendChild(newElement);
}
#console { background-color: yellow; }
#container {
width: 300px;
height: 100px;
background-color: lightblue;
overflow-y: auto;
padding-top: 150px;
margin: 45px;
}
.element {
margin: 400px;
width: 400px;
height: 320px;
background-color: green;
}
#element3 {
position: relative;
margin: 40px;
width: 720px;
height: 520px;
background-color: green;
}
#element3::before {
content: "";
position: absolute;
top: -10px;
left: -10px;
margin: 0px;
width: 740px;
height: 540px;
border: 5px dotted green;
background: transparent;
}
<div id="console"></div>
<div id="container">
<div id="element1" class="element"></div>
<div id="element2" class="element"></div>
<div id="element3" class="element"></div>
</div>
JSFiddle to play with: http://jsfiddle.net/BerkerYuceer/grk5az2c/
This code is made for more precise information if any part of the element is shown in the view or not. For performance options or only vertical slides, do not use this! This code is more effective in drawing cases.
As simple as it can get, IMO:
function isVisible(elem) {
var coords = elem.getBoundingClientRect();
return Math.abs(coords.top) <= coords.height;
}
Here is a function that tells if an element is in visible in the current viewport of a parent element:
function inParentViewport(el, pa) {
if (typeof jQuery === "function"){
if (el instanceof jQuery)
el = el[0];
if (pa instanceof jQuery)
pa = pa[0];
}
var e = el.getBoundingClientRect();
var p = pa.getBoundingClientRect();
return (
e.bottom >= p.top &&
e.right >= p.left &&
e.top <= p.bottom &&
e.left <= p.right
);
}
A better solution:
function getViewportSize(w) {
var w = w || window;
if(w.innerWidth != null)
return {w:w.innerWidth, h:w.innerHeight};
var d = w.document;
if (document.compatMode == "CSS1Compat") {
return {
w: d.documentElement.clientWidth,
h: d.documentElement.clientHeight
};
}
return { w: d.body.clientWidth, h: d.body.clientWidth };
}
function isViewportVisible(e) {
var box = e.getBoundingClientRect();
var height = box.height || (box.bottom - box.top);
var width = box.width || (box.right - box.left);
var viewport = getViewportSize();
if(!height || !width)
return false;
if(box.top > viewport.h || box.bottom < 0)
return false;
if(box.right < 0 || box.left > viewport.w)
return false;
return true;
}
I had the same question and figured it out by using getBoundingClientRect().
This code is completely 'generic' and only has to be written once for it to work (you don't have to write it out for each element that you want to know is in the viewport).
This code only checks to see if it is vertically in the viewport, not horizontally. In this case, the variable (array) 'elements' holds all the elements that you are checking to be vertically in the viewport, so grab any elements you want anywhere and store them there.
The 'for loop', loops through each element and checks to see if it is vertically in the viewport. This code executes every time the user scrolls! If the getBoudingClientRect().top is less than 3/4 the viewport (the element is one quarter in the viewport), it registers as 'in the viewport'.
Since the code is generic, you will want to know 'which' element is in the viewport. To find that out, you can determine it by custom attribute, node name, id, class name, and more.
Here is my code (tell me if it doesn't work; it has been tested in Internet Explorer 11, Firefox 40.0.3, Chrome Version 45.0.2454.85 m, Opera 31.0.1889.174, and Edge with Windows 10, [not Safari yet])...
// Scrolling handlers...
window.onscroll = function(){
var elements = document.getElementById('whatever').getElementsByClassName('whatever');
for(var i = 0; i != elements.length; i++)
{
if(elements[i].getBoundingClientRect().top <= window.innerHeight*0.75 &&
elements[i].getBoundingClientRect().top > 0)
{
console.log(elements[i].nodeName + ' ' +
elements[i].className + ' ' +
elements[i].id +
' is in the viewport; proceed with whatever code you want to do here.');
}
};
This checks if an element is at least partially in view (vertical dimension):
function inView(element) {
var box = element.getBoundingClientRect();
return inViewBox(box);
}
function inViewBox(box) {
return ((box.bottom < 0) || (box.top > getWindowSize().h)) ? false : true;
}
function getWindowSize() {
return { w: document.body.offsetWidth || document.documentElement.offsetWidth || window.innerWidth, h: document.body.offsetHeight || document.documentElement.offsetHeight || window.innerHeight}
}
This is the easy and small solution that has worked for me.
Example: You want to see if the element is visible in the parent element that has overflow scroll.
$(window).on('scroll', function () {
var container = $('#sidebar');
var containerHeight = container.height();
var scrollPosition = $('#row1').offset().top - container.offset().top;
if (containerHeight < scrollPosition) {
console.log('not visible');
} else {
console.log('visible');
}
})
All the answers here are determining if the element is fully contained within the viewport, not just visible in some way. For example, if only half of an image is visible at the bottom of the view, the solutions here will fail, considering that "outside". I had a use case where I'm doing lazy loading via IntersectionObserver, but due to animations that occur during pop-in, I didn't want to observe any images that were already intersected on page load. To do that, I used the following code: const bounding = el.getBoundingClientRect(); const isVisible = (0 < bounding.top && bounding.top < (window.innerHeight || document.documentElement.clientHeight)) || (0 < bounding.bottom && bounding.bottom < (window.innerHeight || document.documentElement.clientHeight)); This is basically checking to see if either the top or bottom bound is independently in the viewport. The opposite end may be outside, but as long as one end is in, it's "visible" at least partially.
I use this function (it only checks if the y is inscreen since most of the time the x is not needed)
function elementInViewport(el) {
var elinfo = {
"top":el.offsetTop,
"height":el.offsetHeight,
};
if (elinfo.top + elinfo.height < window.pageYOffset || elinfo.top > window.pageYOffset + window.innerHeight) {
return false;
} else {
return true;
}
}
Here is a snippet to check if the given element is fully visible in its parent:
export const visibleInParentViewport = (el) => {
const elementRect = el.getBoundingClientRect();
const parentRect = el.parentNode.getBoundingClientRect();
return (
elementRect.top >= parentRect.top &&
elementRect.right >= parentRect.left &&
elementRect.top + elementRect.height <= parentRect.bottom &&
elementRect.left + elementRect.width <= parentRect.right
);
}
const isHTMLElementInView = (element: HTMLElement) => {
const rect = element?.getBoundingClientRect()
if (!rect) return
return rect.top <= window.innerHeight && rect.bottom >= 0
}
This function checks if the element is in the viewport on vertical level.
Domysee's answer https://stackoverflow.com/a/37998526 is close to correct.
Many examples use "completely contained in the viewport" and his code uses percentages to allow for partially visible. His code also addresses the "is a parent clipping the view" question, which most examples ignore.
One missing element is the impact of the parent's scrollbars - getBoundingClientRect returns the outer rectangle of the parent, which includes the scroll bars, not the inner rectangle, which doesn't. A child can hide behind the parent scroll bar and be considered visible when it isn't.
The recommended observer pattern isn't appropriate for my use case: using the arrow keys to change the currently selected row in a table, and make sure the new selection is visible. Using an observer for this would be excessively convoluted.
Here's some code -
it includes an additional hack (fudgeY) because my table has a sticky header that isn't detectable by straightforward means (and handling this automatically would be pretty tedious). Also, it uses decimal (0 to 1) instead of percentage for the required visible fraction. (For my case I need full y, and x isn't relevant).
function intersectRect(r1, r2) {
var r = {};
r.left = r1.left < r2.left ? r2.left : r1.left;
r.top = r1.top < r2.top ? r2.top : r1.top;
r.right = r1.right < r2.right ? r1.right : r2.right;
r.bottom = r1.bottom < r2.bottom ? r1.bottom : r2.bottom;
if (r.left < r.right && r.top < r.bottom)
return r;
return null;
}
function innerRect(e) {
var b,r;
b = e.getBoundingClientRect();
r = {};
r.left = b.left;
r.top = b.top;
r.right = b.left + e.clientWidth;
r.bottom = b.top + e.clientHeight;
return r;
}
function isViewable(e, fracX, fracY, fudgeY) {
// ref https://stackoverflow.com/a/37998526
// intersect all the rects and then check the result once
// innerRect: mind the scroll bars
// fudgeY: handle "sticky" thead in parent table. Ugh.
var r, pr, er;
er = e.getBoundingClientRect();
r = er;
for (;;) {
e = e.parentElement;
if (!e)
break;
pr = innerRect(e);
if (fudgeY)
pr.top += fudgeY;
r = intersectRect(r, pr);
if (!r)
return false;
}
if (fracX && ((r.right-r.left) / (er.right-er.left)) < (fracX-0.001))
return false;
if (fracY && ((r.bottom-r.top) / (er.bottom-er.top)) < (fracY-0.001))
return false;
return true;
}
Enable scrolling event when div is in viewport only once then reset when out of viewport
I'm trying to track an element every time it enters the viewport in Amplitude. Right now when an element is scrolled into view the jQuery detects the elements id, if it was scrolled up or down, and states that it is a scroll event. These items are display in Amplitude admin. The issue is when the div is in viewport the scroll event is fired for EVERY mouse scroll. So it creates a ton of events when only one is need per element in viewport. How do I fire the event only once but then reset it once its out of viewport again?
function isScrolledIntoView(elem) {
// set offset by 10%
var offSet = jQuery(window).height()*0.1;
// offset scrolltop
var docViewTop = jQuery(window).scrollTop() + offSet;
// set window height area to 80%
var windowSize = jQuery(window).height()*0.8;
var docViewBottom = docViewTop + windowSize;
var elemTop = jQuery(elem).offset().top;
var elemBottom = elemTop + jQuery(elem).height();
return ((elemBottom <= docViewBottom) && (elemTop >= docViewTop));
}
var lastScrollTop = 0;
jQuery(window).scroll(function (event) {
// detects scroll direction.
var st = jQuery(this).scrollTop();
if (st > lastScrollTop){
var action = 'ScrollDown';
} else {
var action = 'ScrollUp';
}
lastScrollTop = st;
jQuery('.trackScrolling').each(function () {
// get element ID
var elementID = jQuery(this).attr("id");
var ScrollEvents = 'ScrollEvents';
// if in viewport fire event
if (isScrolledIntoView(this) === true) {
gu_event(ScrollEvents, action, elementID);
}
});
});
You'll need to create a boolean flag for each element to check if it is already in the viewport and add another if condition checking for it, something like this:
var elements = [];
var lastScrollTop = 0;
jQuery('.trackScrolling').each(function () {
elements.push({
"elem": this,
"id": jQuery(this).attr("id")),
"inView": false
});
});
function isScrolledIntoView(elem) {
// set offset by 10%
var offSet = jQuery(window).height()*0.1;
// offset scrolltop
var docViewTop = jQuery(window).scrollTop() + offSet;
// set window height area to 80%
var windowSize = jQuery(window).height()*0.8;
var docViewBottom = docViewTop + windowSize;
var elemTop = jQuery(elem).offset().top;
var elemBottom = elemTop + jQuery(elem).height();
return ((elemBottom <= docViewBottom) && (elemTop >= docViewTop));
}
jQuery(window).scroll(function (event) {
var action;
// detects scroll direction.
var st = jQuery(this).scrollTop();
if (st > lastScrollTop){
action = 'ScrollDown';
} else {
action = 'ScrollUp';
}
lastScrollTop = st;
for (var i = 0; i < elements.length; i++) {
var ScrollEvents = 'ScrollEvents';
if (elements[i].inView === true && isScrolledIntoView(elements[i].elem) === true) {
// do nothing in this case...
console.log('Element ' + elements[i].id + ' is already in view!');
} else if (isScrolledIntoView(elements[i].elem) === true) {
// set the flag in this case and send the event
elements[i].inView = true;
gu_event(ScrollEvents, action, elements[i].id);
} else if (isScrolledIntoView(elements[i].elem) === false) {
// reset the flag in this case
elements[i].inView = false;
}
}
});
Instead of your scroll function continually finding all of the .trackScrolling elements, I've stored a reference to them upfront - the ID of each and whether it's in the viewport are stored in an object.
Check if element is in viewport inside iframe
I have one page which contains Iframe, iframe has few elements that need to be loaded only if it's in viewport.
But iframe is not scrollable, only master page has scroll. I have written following function but its not working if used with master page.
function isVisible(a) {
var b1 = a.getBoundingClientRect(),
b={},
c = window.innerWidth || doc.documentElement.clientWidth,
d = window.innerHeight || doc.documentElement.clientHeight,
e = function(a, b) {
return document.elementFromPoint(a, b)
};
if(window.frameElement){
var w = window.frameElement.getBoundingClientRect();
// d = window.innerHeight || doc.documentElement.clientHeight;
for( var i in b1){
b[i]=Math.abs(b1[i])+Math.abs(w[i])
}
}else{
b=b1;
}
return !(b.right < 0 || b.bottom < 0 || b.left > c || b.top > d) && (a.contains(e(b.left, b.top)) || a.contains(e(b.right, b.top)) || a.contains(e(b.right, b.bottom)) || a.contains(e(b.left, b.bottom)))
}
Please suggest a way forward, thanks in advance .
This will defer loading of the iframe content until it is scrolled into view.
JSFiddle Example
var $iframe = $("#iframe");
$(window).on("scroll", function() {
// you should probably throttle or debounce this method; I didn't
if (isScrolledIntoView($iframe[0])) {
// assumes same origin for iframe
// if iframe has window object and function "viewportUpdate" call function
var iframeWindow = $iframe[0].contentWindow;
if (iframeWindow && iframeWindow.viewportUpdate)
{
var docViewTop = $(window).scrollTop();
var docViewBottom = docViewTop + $(window).height();
iframeWindow.viewportUpdate(docViewTop, docViewBottom);
}
}
});
// from http://stackoverflow.com/questions/487073/check-if-element-is-visible-after-scrolling
function isScrolledIntoView(elem) {
var docViewTop = $(window).scrollTop();
var docViewBottom = docViewTop + $(window).height();
var elemTop = $(elem).offset().top;
var elemBottom = elemTop + $(elem).height();
return ((elemBottom <= docViewBottom) && (elemTop >= docViewTop));
}
iframe content uses this method to do your magic:
function viewportUpdate(docViewTop, docViewBottom)
{
// do your magic here.. whatever that is
// for example, loop over each "img" element and log to console if in view
$("img").each(function()
{
var elemTop = $(elem).offset().top;
var elemBottom = elemTop + $(elem).height();
var elementIsInView = (elemBottom <= docViewBottom) && (elemTop >= docViewTop);
if (elementIsInView)
{
console.log("iframe img element is in view");
}
});
}
Invoke function only if above particular div
I have a div that becomes 'fixed' to the bottom of the window once it is scrolled out of view. I only want this behavior when the user is viewing the top half of the page. I do not want a fixed state being applied to the div when the user is on the bottom part of the page.
In short - The issue I have is that a fixed state is being applied when the div is out of view, regardless of page position.
Demo https://jsfiddle.net/DTcHh/19352/
$(window).scroll(function() {
if (isScrolledIntoView($('#myDivWrapper'))) {
if (!initSet) {
initSet = true;
}
$("#myDiv").removeClass('fixed');
} else if (initSet) {
$("#myDiv").addClass('fixed');
}
});
function isScrolledIntoView(elem) {
var $elem = $(elem);
var $window = $(window);
var docViewTop = $window.scrollTop();
var docViewBottom = docViewTop + $window.height();
var elemTop = $elem.offset().top;
var elemBottom = elemTop + $elem.height();
return ((elemBottom <= docViewBottom) && (elemTop >= docViewTop));
}
This method involves editing your markup and your isScrolledIntoView function.
Wrap the top half (or whatever viewable area you want invoked) of your markup in a div give it an id of #top.
Modify your scroll markup as this is currently checking that ALL of the element is in view, you only want a partial check.
Demo https://jsfiddle.net/DTcHh/19366/
$(window).scroll(function() {
if(isScrolledIntoView($('#myDivWrapper'))) {
if (!initSet) {
initSet = true;
}
$("#myDiv").removeClass('fixed');
} else if (initSet && isScrolledIntoView($('#top'))) {
$("#myDiv").addClass('fixed');
}
});
function isScrolledIntoView(elem) {
var $elem = $(elem);
var $window = $(window);
var docViewTop = $window.scrollTop();
var docViewBottom = docViewTop + $window.height();
var elemTop = $elem.offset().top;
var elemBottom = elemTop + $elem.height();
return ((elemTop <= docViewBottom) && (elemBottom >= docViewTop)) ;
}
I would suggest modifying the isScrolledIntoView function so it accepts a second parameter/ele. This way you'd only need to call it once.
This if block will execute only if you are on lower half of the page if($(window).scrollTop() + $(window).height()/2 > $(document).height() / 2) updated fiddle - https://jsfiddle.net/DTcHh/19370/
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... */ };