I have a simple function which detects if an element is in the viewport or that it is visible. If that element is visible, on every scroll I move that element down with .css() and change the top property to achieve some parallax effect. This element on which I check is in the viewport and when it moves it is repeated X times on the page. Everything works but only on the first element has this problem, all other elements inherit top position from the first.
Demo: http://codepen.io/riogrande/pen/RRVVwq (scroll down for effect).
EDIT: Some who answered had the wrong idea what I want, so I want the title (element) to move on scroll but only when its in viewport(visible). So when the first element with same class is visible its moving with scroll, then when you scroll below it its not visible anymore it should not move but the other one which is visible should be moving etc etc.
Jquery:
(function($) {
'use strict';
$.prototype.isVisible = function() {
var rect = this[0].getBoundingClientRect();
return (
(rect.height > 0 || rect.width > 0) &&
rect.bottom >= 0 &&
rect.right >= 0 &&
rect.top <= (window.innerHeight || document.documentElement.clientHeight) &&
rect.left <= (window.innerWidth || document.documentElement.clientWidth)
);
};
function doCheck() {
var elementToDetect = $('.text');
var scrolled = $(window).scrollTop();
if (elementToDetect.isVisible()) {
elementToDetect.css('top', (-100 + (scrolled * 0.2)) + 'px');
}
}
$(document).ready(function() {
doCheck();
});
$(window).scroll(function() {
doCheck();
});
})(jQuery);
jQuery applies operations like css() on each element matching the selector.
So if you iterate the jQuery object, you get this:
function doCheck() {
var elementToDetect = $('.text');
var scrolled = $(window).scrollTop();
for (var index = 0; index < elementToDetect.length; index++) {
var element = $(elementToDetect[index]);
if (element.isVisible()) {
element.css('top', (-100 + (scrolled * 0.2)) + 'px');
}
}
}
Which still has a problem, in that all the text maintain the same top relative to their image.
Edit:
Actually, the way I understand what you're doing, you want to let them all move in the same way as you scroll, so each starts above the image when it comes into view. This is closer to what you need:
function doCheck() {
var elementToDetect = $('.text');
for (var index = 0; index < elementToDetect.length; index++) {
var text = elementToDetect[index];
var parent = text.parentElement;
var parentTop = parent.getBoundingClientRect().top;
var scrolled = (window.innerHeight - parentTop);
if (scrolled < 0) {
scrolled = 0;
}
if (parentTop < window.innerHeight) {
$(text).css('top', (-100 + (scrolled * 0.2)) + 'px');
}
}
}
Basically, looking at scrollTop() is wrong, because you really want the position of the parent div to determine the placement of your text.
Here you need to check for each .text on the scroll:
function doCheck() {
var elementToDetect = $('.text');
var scrolled = $(window).scrollTop();
elementToDetect.each(function(i, txtEl) {
if (txtEl.isVisible()) {
txtEl.css('top', (-100 + (scrolled * 0.2)) + 'px');
}
});
}
And most likely you want to have a debouce there in the window.scroll:
var timer;
$(window).scroll(function() {
if(timer){ clearTimeout(timer); }
timer = setTimeout(function(){
doCheck();
}, 900);
});
$('.text') returns an array of elements. You need to apply the css transform to each item rather than the array of items. The below code may require an update to get the output you would like but I think it should get you going.
function doCheck() {
var scrolled = $(window).scrollTop();
$('.text').each(function() {
if($(this).isVisible()) {
$(this).css('top', (-100 + (scrolled * 0.2)) + 'px');
}
})
}
This is my current solution to check if a specific div reaches the top of the page, which i got from here https://stackoverflow.com/a/5279537/4671165
document.addEventListener("scroll", Scroll, false);
function Scroll() {
var top = $('.element').offset().top - $(document).scrollTop();
if (top < 150){
var textvariable = $('.text').text();
}
}
But i want this to do something each time a different div reaches the top of the page, therefore i currently have
var top1 = $('.element1').offset().top - $(document).scrollTop();
var top2 = $('.element2').offset().top - $(document).scrollTop();
var top3 = $('.element3').offset().top - $(document).scrollTop();
if (top1 < 150 && top2 > 150){
var textvariable = $('.text1').text();
}
if (top1 < 150 && top2 < 150 && top3 > 250){
var textvariable = $(.text2').text();
}
if (top2 < 150 && top3 < 250){
var textvariable = $(.text3').text();
}
However, this doesn't seem the most effective way but i can't figure out what is. Especially since i have more elements then just 3 in the project. So i am looking for a more effective way.
I put this together using ES6. I believe this should work. It's been a while since I've used getBoundingClientRect() though.
var divs = document.querySelectAll('div');
document.addEventListener("scroll", Scroll, false);
function Scroll() {
divs.forEach((memo,index) => {
let divTop = memo.getBoundingClientRect().top;
if (divTop <= 0) {
var textvariable = $('.text' + index).text();
});
}
Hope this helps. It should be easier to use and it has a lot of bugs already fixed for you. It's a 1.82 kb file so there's not really much useless stuff into it if added.
I found a jquery solution
function ScrollStart() {
var scrolled = $(this).scrollTop();
/*filter current element at the top with a certain class & give it active class*/
$('.step').removeClass('activetext').filter(function() {
return scrolled <= $(this).offset().top + $(this).height() - 50 && scrolled >= $(this).offset().top - 50;
}).addClass('activetext');
/* make exclusion for first element */
var boven = $('.first').offset().top - $(document).scrollTop();
if (boven > 0){
$('.first').addClass('activetext');
}
/*make exclusion for last element*/
var bottom = $('.last').offset().top - ($('.last').height()/5) - $(document).scrollTop();
if (bottom < 150){
$('.step').removeClass('activetext')
$('.last').addClass('activetext');
}
else{
$('.last').removeClass('activetext')
}
/* give variable 'text' the text of the active class & append it */
var text = $('.activetext .headertekst').text();
$('.dropbtn').empty();
$('.dropbtn').append(text);
$('.dropbtn').append('<img src="images/downarrow.svg" galleryimg="no"></img>');
}
I'm trying to get this div to stop at the bottom but for some reason once it reaches the bottom it starts jumping around.
Any ideas? It seems like even when bottom_offset < 181 it still keeps changing the css top property.
<script>
jQuery(document).ready(function() {
var el = jQuery('#contactBox');
top_offset = jQuery('#contactBox').offset().top - 60;
var box_height = el.height();
jQuery(window).scroll(function() {
var scroll_top = jQuery(window).scrollTop();
var bottom_offset = jQuery(document).height() - scroll_top - box_height;
var new_top_offset = jQuery(document).height() - box_height - 100;
if ((scroll_top > top_offset) && (bottom_offset > 180)) {
el.css('top', scroll_top - top_offset);
}
else if ((scroll_top > top_offset) && (bottom_offset < 181)) {
el.css('top', new_top_offset);
}
else {
el.css('top', '');
}
});
});
</script>
Not sure how the html and css is setup so I'm taking a guess.
If the div has a fixed position, you can remove the following code and it should stop at the bottom.
The new_top_offset made the div jump down when i scrolled near the bottom.
else if ((scroll_top > top_offset) && (bottom_offset < 181)) {
el.css('top', new_top_offset);
}
else {
el.css('top', '');
Well I went ahead and changed it so that it worked a bit differently. It would just calculate body height minus footer height and also do scroll top + height of the scrolling div, and then it only changes css if total_height < body_height.
Here's the code if anyone needs it in the future.
jQuery(document).ready(function() {
var el = jQuery('#contactBox');
top_offset = jQuery('#contactBox').offset().top - 60;
var box_height = el.height();
jQuery(window).scroll(function() {
var scroll_top = jQuery(window).scrollTop();
var total_height = scroll_top + box_height;
var body_height = jQuery('body').outerHeight() - 150;
if ((scroll_top > top_offset) && (total_height < body_height)) {
el.css('top', scroll_top - top_offset);
}
});
});
I have a floating div on the sidebar that scrolls with the page. Is there a way to add code that makes it stop when it reaches the footer?
See code in action: http://openbayou.staging.wpengine.com
jQuery code used to float div:
$j=jQuery.noConflict();
$j(document).ready(function($) {
//this is the floating content
var $floatingbox = $('#one');
if($('#primary').length > 0){
var bodyY = parseInt($('#primary').offset().top) - 20;
var originalX = $floatingbox.css('margin-left');
$(window).scroll(function () {
var scrollY = $(window).scrollTop();
var isfixed = $floatingbox.css('position') == 'fixed';
if($floatingbox.length > 0){
$floatingbox.html();
if ( scrollY > 1561 && !isfixed ) {
$floatingbox.stop().css({
position: 'fixed',
top: 10,
});
} else if ( scrollY < 1561 && isfixed ) {
$floatingbox.css({
position: 'relative',
top: 0,
});
}
}
});
}
});
Why not just set the z-index of the sidebar behind the z-index of the footer?
EDIT: I didn't like the result of this so I went and made this work in jquery the way you want it...
try this for your scroll function:
$(window).scroll(function () {
floatingbox = $("#one");
if(floatingbox.length > 0){
//get our current scroll position
var scrollY = $(window).scrollTop();
//get the position of the tag cloud relative to the document
var contentY = ($("#sidebar .sidebar-tag-cloud").offset().top + $("#sidebar .sidebar-tag-cloud").outerHeight(false));
//calculate the largest possible top margin size before it starts to overlap the footer
var lastY = $("#footer").offset().top - $("#one").outerHeight(false);
//check if our scroll location is past the bottom of the tag cloud
if ( scrollY > contentY )
{
//check if the current top position is less than the maximum position
if(floatingbox.offset().top<lastY)
{
//keep scrolling
floatingbox.stop().animate({"marginTop":scrollY-contentY});
}else
{
//check if we have scrolled back up and have a space at the top
if(scrollY<floatingbox.offset().top)
{
floatingbox.stop().animate({"marginTop":scrollY-contentY});
}else
{
// hard set to the maximum position
floatingbox.stop().css({"marginTop":lastY-contentY});
}
}
}
}
});
I also made it a little more dynamic by getting the location of the bottom of the tag cloud and using that instead of your hard-coded number.
Alright, after looking at your latest jsfiddle. I have modified that code to work with yours. http://jsfiddle.net/Tgm6Y/4430/ This will not have the animate lag and should work well for you.
$('#one').followTo('#two','#pointFive');
just replace #two with #footer and #pointFive with "#sidebar .sidebar-tag-cloud" and this should work in your code.
UPDATE: Found a solution to my problem.
$(function () {
var msie6 = $.browser == 'msie' && $.browser.version < 7;
if (!msie6) {
var top = $('#one').offset().top;
$(window).scroll(function (event) {
var y = $(this).scrollTop() + 20;
if (y >= top) {
$('#one').addClass('fixed');
}
else {
$('#one').removeClass('fixed');
}
// don't overlap the footer - pull sidebar up using a negative margin
footertotop = ($('#footer').position().top);
scrolltop = $(document).scrollTop() + 760;
difference = scrolltop - footertotop;
if (scrolltop > footertotop) {
$('#one').css('margin-top', 0 - difference);
}
else {
$('#one').css('margin-top', 0);
}
});
}
});
What this does is it stops before the footer and I can configure the stopping point.
I appreciate all the help in solving my problem!
how to determine, using jquery, if the element is visible on the current page view. I'd like to add a comment functionality, which works like in facebook, where you only scroll to element if it's not currently visible. By visible, I mean that it is not in the current page view, but you can scroll to the element.
Live Demo
Basically you just check the position of the element to see if its within the windows viewport.
function checkIfInView(element){
var offset = element.offset().top - $(window).scrollTop();
if(offset > window.innerHeight){
// Not in view so scroll to it
$('html,body').animate({scrollTop: offset}, 1000);
return false;
}
return true;
}
Improving Loktar's answer, fixing the following:
Scroll up
Scroll to a display:none element (like hidden div's etc)
function scrollToView(element){
var offset = element.offset().top;
if(!element.is(":visible")) {
element.css({"visibility":"hidden"}).show();
var offset = element.offset().top;
element.css({"visibility":"", "display":""});
}
var visible_area_start = $(window).scrollTop();
var visible_area_end = visible_area_start + window.innerHeight;
if(offset < visible_area_start || offset > visible_area_end){
// Not in view so scroll to it
$('html,body').animate({scrollTop: offset - window.innerHeight/3}, 1000);
return false;
}
return true;
}
After trying all these solutions and many more besides, none of them satisfied my requirement for running old web portal software (10 years old) inside IE11 (in some compatibility mode). They all failed to correctly determine if the element was visible. However I found this solution. I hope it helps.
function scrollIntoViewIfOutOfView(el) {
var topOfPage = window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop;
var heightOfPage = window.innerHeight || document.documentElement.clientHeight || document.body.clientHeight;
var elY = 0;
var elH = 0;
if (document.layers) { // NS4
elY = el.y;
elH = el.height;
}
else {
for(var p=el; p&&p.tagName!='BODY'; p=p.offsetParent){
elY += p.offsetTop;
}
elH = el.offsetHeight;
}
if ((topOfPage + heightOfPage) < (elY + elH)) {
el.scrollIntoView(false);
}
else if (elY < topOfPage) {
el.scrollIntoView(true);
}
}
I made a slightly more generic version of digitalPBK's answer that minimally scrolls an element contained within a div or some other container (including the body). You can pass DOM elements or selectors to the function, as long as the element is somehow contained within the parent.
function scrollToView(element, parent) {
element = $(element);
parent = $(parent);
var offset = element.offset().top + parent.scrollTop();
var height = element.innerHeight();
var offset_end = offset + height;
if (!element.is(":visible")) {
element.css({"visibility":"hidden"}).show();
var offset = element.offset().top;
element.css({"visibility":"", "display":""});
}
var visible_area_start = parent.scrollTop();
var visible_area_end = visible_area_start + parent.innerHeight();
if (offset-height < visible_area_start) {
parent.animate({scrollTop: offset-height}, 600);
return false;
} else if (offset_end > visible_area_end) {
parent.animate({scrollTop: parent.scrollTop()+ offset_end - visible_area_end }, 600);
return false;
}
return true;
}
You can take a look at his awesome link from the jQuery Cookbook:
Determining Whether an Element Is Within the Viewport
Test if Element is contained in the Viewport
jQuery(document).ready(function() {
var viewportWidth = jQuery(window).width(),
viewportHeight = jQuery(window).height(),
documentScrollTop = jQuery(document).scrollTop(),
documentScrollLeft = jQuery(document).scrollLeft(),
$myElement = jQuery('#myElement'),
elementOffset = $myElement.offset(),
elementHeight = $myElement.height(),
elementWidth = $myElement.width(),
minTop = documentScrollTop,
maxTop = documentScrollTop + viewportHeight,
minLeft = documentScrollLeft,
maxLeft = documentScrollLeft + viewportWidth;
if (
(elementOffset.top > minTop && elementOffset.top + elementHeight < maxTop) &&
(elementOffset.left > minLeft && elementOffset.left + elementWidth < maxLeft)
) {
alert('entire element is visible');
} else {
alert('entire element is not visible');
}
});
Test how much of the element is visible
jQuery(document).ready(function() {
var viewportWidth = jQuery(window).width(),
viewportHeight = jQuery(window).height(),
documentScrollTop = jQuery(document).scrollTop(),
documentScrollLeft = jQuery(document).scrollLeft(),
$myElement = jQuery('#myElement'),
verticalVisible, horizontalVisible,
elementOffset = $myElement.offset(),
elementHeight = $myElement.height(),
elementWidth = $myElement.width(),
minTop = documentScrollTop,
maxTop = documentScrollTop + viewportHeight,
minLeft = documentScrollLeft,
maxLeft = documentScrollLeft + viewportWidth;
function scrollToPosition(position) {
jQuery('html,body').animate({
scrollTop : position.top,
scrollLeft : position.left
}, 300);
}
if (
((elementOffset.top > minTop && elementOffset.top < maxTop) ||
(elementOffset.top + elementHeight > minTop && elementOffset.top +
elementHeight < maxTop))
&& ((elementOffset.left > minLeft && elementOffset.left < maxLeft) ||
(elementOffset.left + elementWidth > minLeft && elementOffset.left +
elementWidth < maxLeft)))
{
alert('some portion of the element is visible');
if (elementOffset.top >= minTop && elementOffset.top + elementHeight
<= maxTop) {
verticalVisible = elementHeight;
} else if (elementOffset.top < minTop) {
verticalVisible = elementHeight - (minTop - elementOffset.top);
} else {
verticalVisible = maxTop - elementOffset.top;
}
if (elementOffset.left >= minLeft && elementOffset.left + elementWidth
<= maxLeft) {
horizontalVisible = elementWidth;
} else if (elementOffset.left < minLeft) {
horizontalVisible = elementWidth - (minLeft - elementOffset.left);
} else {
horizontalVisible = maxLeft - elementOffset.left;
}
var percentVerticalVisible = (verticalVisible / elementHeight) * 100;
var percentHorizontalVisible = (horizontalVisible / elementWidth) * 100;
if (percentVerticalVisible < 50 || percentHorizontalVisible < 50) {
alert('less than 50% of element visible; scrolling');
scrollToPosition(elementOffset);
} else {
alert('enough of the element is visible that there is no need to scroll');
}
} else {
// element is not visible; scroll to it
alert('element is not visible; scrolling');
scrollToPosition(elementOffset);
}
The following code helped me achieve the result
function scroll_to_element_if_not_inside_view(element){
if($(window).scrollTop() > element.offset().top){
$('html, body').animate( { scrollTop: element.offset().top }, {duration: 400 } );
}
}
Here is the solution I came up with, working both up and down and using only Vanilla Javascript, no jQuery.
function scrollToIfNotVisible(element) {
const rect = element.getBoundingClientRect();
// Eventually an offset corresponding to the height of a fixed navbar for example.
const offset = 70;
let scroll = false;
if (rect.top < offset) {
scroll = true;
}
if (rect.top > window.innerHeight) {
scroll = true;
}
if (scroll) {
window.scrollTo({
top: (window.scrollY + rect.top) - offset,
behavior: 'smooth'
})
}
}
There is a jQuery plugin which allows us to quickly check if a whole element (or also only part of it) is within the browsers visual viewport regardless of the window scroll position. You need to download it from its GitHub repository:
Suppose to have the following HTML and you want to alert when footer is visible:
<section id="container">
<aside id="sidebar">
<p>
Scroll up and down to alert the footer visibility by color:
</p>
<ul>
<li><span class="blue">Blue</span> = footer <u>not visible</u>;</li>
<li><span class="yellow">Yellow</span> = footer <u>visible</u>;</li>
</ul>
<span id="alert"></span>
</aside>
<section id="main_content"></section>
</section>
<footer id="page_footer"></footer>
So, add the plugin before the close of body tag:
<script type="text/javascript" src="js/jquery-1.12.0.min.js"></script>
<script type="text/javascript" src="js/jquery_visible/examples/js/jq.visible.js"></script>
After that you can use it in a simple way like this:
<script type="text/javascript">
jQuery( document ).ready(function ( $ ) {
if ($("footer#page_footer").visible(true, false, "both")) {
$("#main_content").css({"background-color":"#ffeb3b"});
$("span#alert").html("Footer visible");
} else {
$("#main_content").css({"background-color":"#4aafba"});
$("span#alert").html("Footer not visible");
}
$(window).scroll(function() {
if ($("footer#page_footer").visible(true, false, "both")) {
$("#main_content").css({"background-color":"#ffeb3b"});
$("span#alert").html("Footer visible");
} else {
$("#main_content").css({"background-color":"#4aafba"});
$("span#alert").html("Footer not visible");
}
});
});
</script>
Here a demo
No-JQuery version.
The particular case here is where the scroll container is the body (TBODY, table.body) of a TABLE (scrolling independently of THEAD). But it could be adapted to any situation, some simpler.
const row = table.body.children[ ... ];
...
const bottomOfRow = row.offsetHeight + row.offsetTop ;
// if the bottom of the row is in the viewport...
if( bottomOfRow - table.body.scrollTop < table.body.clientHeight ){
// ... if the top of the row is in the viewport
if( row.offsetTop - table.body.scrollTop > 0 ){
console.log( 'row is entirely visible' );
}
else if( row.offsetTop - table.body.scrollTop + row.offsetHeight > 0 ){
console.log( 'row is partly visible at top')
row.scrollIntoView();
}
else {
console.log( 'top of row out of view above viewport')
row.scrollIntoView();
}
}
else if( row.offsetTop - table.body.scrollTop < table.body.clientHeight ){
console.log( 'row is partly visible at bottom')
row.scrollIntoView();
}
else {
console.log( 'row is out of view beneath viewport')
row.scrollIntoView();
}
I think this is the complete answer. An elevator must be able to go both up and down ;)
function ensureVisible(elementId, top = 0 /* set to "top-nav" Height (if you have)*/) {
let elem = $('#elementId');
if (elem) {
let offset = elem.offset().top - $(window).scrollTop();
if (offset > window.innerHeight) { // Not in view
$('html,body').animate({ scrollTop: offset + top }, 1000);
} else if (offset < top) { // Should go to top
$('html,body').animate({ scrollTop: $(window).scrollTop() - (top - offset) }, 1000);
}
}
}