How to add animation to the active div on window scroll? - javascript

I have multiple divs in my page. This div contains size and color. When scroll down, div visible to the screen should move up and when scroll up, it should return to its original position.
This is the code so far I have tried. With this code, when I scroll down, div is moving up but when I scroll up , div is not coming down. Can anybody please help me?
function isElementInViewport(el) {
if (typeof jQuery === "function" && el instanceof jQuery) {
el = el[0];
}
var rect = el.getBoundingClientRect();
return (
(rect.top <= 0 &&
rect.bottom >= 0) ||
(rect.bottom >= (window.innerHeight || document.documentElement.clientHeight) &&
rect.top <= (window.innerHeight || document.documentElement.clientHeight)) ||
(rect.top >= 0 &&
rect.bottom <= (window.innerHeight || document.documentElement.clientHeight))
);
}
window.addEventListener('scroll', function(e) {
winScrollTop = $(this).scrollTop();
var elementsToShow = document.querySelectorAll('.rectangle');
Array.prototype.forEach.call(elementsToShow, function(element) {
if (isElementInViewport(element)) {
element.classList.add('is-visible');
} else {
element.classList.remove('is-visible');
}
});
});
.rectangle {
background-color: red;
height: 444px;
width: 100px;
/* margin-top: -98px; */
z-index: -30;
transition: 0.5s;
transform: translateY(-98px);
margin-bottom: 25px;
}
.is-visible {
transform: translateY(-250px);
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="rectangle"></div>
<div class="rectangle"></div>
<div class="rectangle"></div>
<div class="rectangle"></div>

So what i did over here is that firstly i checked the scroll event and then decided if the scroll was actually upwards or downwards. Once i identified whether i was scrolling upwards or downwards, i added the classes respectively. For the not-visible class i am setting style transform: translateY(0px) which simply returns the element to its default place.
.not-visible{
transform: translateY(0px);
}
var lastScrollTop= 0;
window.addEventListener('scroll', function(e) {
winScrollTop = $(this).scrollTop();
var st = window.pageYOffset || document.documentElement.scrollTop; // Credits:
var elementsToShow = document.querySelectorAll('.rectangle');
if (st > lastScrollTop){ // If st is greater than lastscrollTop then it is downward
console.log("down");
// then check if elemetnts are in view
Array.prototype.forEach.call(elementsToShow, function(element) {
if (isElementInViewport(element)) {
element.classList.remove('not-visible'); // remove class notvisible if any
element.classList.add('is-visible'); // Add class isvisible
}
lastScrollTop = st <= 0 ? 0 : st; // For Mobile or negative scrolling
});
} else {
console.log("up");
Array.prototype.forEach.call(elementsToShow, function(element) {
if (isElementInViewport(element)) {
// Remove class isvisible and add class not visible to move the element to default place
element.classList.remove('is-visible');
element.classList.add('not-visible');
}
lastScrollTop = st <= 0 ? 0 : st; // For Mobile or negative scrolling
});
}
});

Related

How can I change my code to make the items stay visible after been scrolled over once?

How can I change my code to make the items stay visible after they have been scrolled over once? I am a really beginner at coding, so any help and tips are welcome. Thank you for your help in advance!
.inline-photo {
opacity: 0;
transform: translateY(60px) ;
transition: transform 3000ms 500ms cubic-bezier(0,1,.3,1),
opacity 300ms 500ms ease-out;
will-change: transform, opacity;
}
.inline-photo.is-visible {
opacity: 1;
transform: rotateZ(0deg);
}
var scroll = window.requestAnimationFrame ||
function(callback){ window.setTimeout(callback, 1000/60)};
var elementsToShow = document.querySelectorAll('.show-on-scroll');
function loop() {
elementsToShow.forEach(function (element) {
if (isElementInViewport(element)) {
element.classList.add('is-visible');
} else {
element.classList.remove('is-visible');
}
});
scroll(loop);
}
loop();
function isElementInViewport(el) {
if (typeof jQuery === "function" && el instanceof jQuery) {
el = el[0];
}
var rect = el.getBoundingClientRect();
return (
(rect.top <= 0
&& rect.bottom >= 0)
||
(rect.bottom >= (window.innerHeight || document.documentElement.clientHeight) &&
rect.top <= (window.innerHeight || document.documentElement.clientHeight))
||
(rect.top >= 0 &&
rect.bottom <= (window.innerHeight || document.documentElement.clientHeight))
);
}
My end goal is to get the stay visible after they have appeared once.
Separate logic from appliance within your CSS.
Create a class that applies the visibility.
.inline-photo.is-shown {
opacity: 1;
transform: rotateZ(0deg);
}
And let is-visible manage the state in your code.
if (isElementInViewport(element)) {
element.classList.add('is-visible', 'is-shown');
} else {
element.classList.remove('is-visible');
}

How to change background color on scroll in javascript

I am working on a wordpress website on localhost and using plugin script and style for custom javascript.
I want to change the background color when scroll value changes e.g.
scroll value 0-100 then color red
scroll value 100-200 then color blue
scroll value 200-300 then color pink
scroll value 300-400 then color black
scroll value 400-500 then color orange
by this code i am able to add only one class in first condition of javascript.
.site-main{
background-color:green !important;
}
.scrolled1{
background-color:yellow !important;
}
.scrolled2{
background-color:pink !important;
}
.scrolled3{
background-color:black !important;
}
.scrolled4{
background-color:orange !important;
}
.scrolled5{
background-color:red !important;
}
<script>
alert("success");
window.onscroll = function() {myFunction()};
function myFunction() {
if((document.body.scrollTop > 0 || document.documentElement.scrollTop > 0) && (document.body.scrollTop < 100 || document.documentElement.scrollTop < 100)){
document.getElementById("main").className = "scrolled2";
}
else if((document.body.scrollTop > 100 || document.documentElement.scrollTop > 100) && (document.body.scrollTop < 200 || document.documentElement.scrollTop < 200)){
document.getElementById("main").className = "scrolled3";
}
else {
document.getElementById("main").className = "site-main";
}
}
</script>
Please check it. If you need to have #main green when page loaded, just add .site-main class to your div in html.
window.onscroll = function() {myFunction()};
function myFunction() {
var scrollTop = document.body.scrollTop || document.documentElement.scrollTop;
var elem = document.getElementById("main");
if (scrollTop > 0 && scrollTop < 101) {
elem.className = "scrolled5";
} else if (scrollTop > 100 && scrollTop < 201) {
elem.className = "scrolled6";
} else if (scrollTop > 200 && scrollTop < 301) {
elem.className = "scrolled2";
} else if (scrollTop > 300 && scrollTop < 401) {
elem.className = "scrolled3";
} else if (scrollTop > 400 && scrollTop < 501) {
elem.className = "scrolled4";
} else {
elem.className = "site-main";
}
}
.site-main{
background-color:green !important;
}
.scrolled1{
background-color:yellow !important;
}
.scrolled2{
background-color:pink !important;
}
.scrolled3{
background-color:black !important;
}
.scrolled4{
background-color:orange !important;
}
.scrolled5{
background-color:red !important;
}
.scrolled6 {
background-color: blue !important;
}
<div id="main" style="height: 10000px;"></div> <!-- temporary height -->

PagePiling.js determine if elements are in view

I'm attempting to animate some text when they come into view. Things work fine but when I introduce pagepiling.js, my function for determining if my elements are in view returns false. Here is the function:
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 + window.innerHeight) &&
left < (window.pageXOffset + window.innerWidth) &&
(top + height) > window.pageYOffset &&
(left + width) > window.pageXOffset
);
}
Any ideas on what could be wrong?
Please check how to use of the pagePiling.js callbacks for that such as afterLoad and onLeave.
You can also check the available example within the examples folder of the github repo.
This function should work:
function isInView(el) {
let bb = el.getBoundingClientRect();
return bb.top <= window.innerHeight && bb.bottom >= 0
&& bb.left <= window.innerWidth && bb.right >= 0;
}
Here is a demo:
document.onscroll = function() {
document.querySelector('.status').textContent = isInView(document.querySelector('.element')) ? 'IN' : 'OUT';
}
function isInView(el) {
let bb = el.getBoundingClientRect();
return bb.top <= window.innerHeight && bb.bottom >= 0
&& bb.left <= window.innerWidth && bb.right >= 0;
}
.before,
.element,
.after {
height: 200vh;
background: wheat;
}
.element {
background: teal;
}
.status {
position: fixed;
top: 20px;
right: 20px;
padding: 1em;
background: silver;
}
<div class="before">Before</div>
<div class="element">Element</div>
<div class="after">After</div>
<div class="status">...</div>

if window scroll amount -> then reverse back in jQuery

jQuery:
$(window).scroll(function() {
var scroll = $(window).scrollTop();
if (scroll >= 50) {
$(".class").addClass("bgposi");
// $(".top").addClass("fixd");
// $(".logo").addClass("maxwidth");
if (scroll >= 50) {
$(".class").addClass("bgposi");
// $(".top").addClass("fixd");
// $(".logo").addClass("maxwidth");
}
}
});
So, basically my class that I'm adding on scroll. .bgposi is moving the background image position when I scroll past 50px on the page using (window).scroll(function(). Which works fine, so my first if statement alone.. However, I'm trying to reverse it with another if statement, when the user scrolls back up - this is where I'm failing.. any pointers?
Correct the following in your second if statement:
Do not nest it.
Change the comparison operator >= to <=.
Use removeClass.
Change:
$(window).scroll(function() {
var scroll = $(window).scrollTop();
if (scroll >= 50) {
$(".class").addClass("bgposi");
// $(".top").addClass("fixd");
// $(".logo").addClass("maxwidth");
if (scroll >= 50) {
$(".class").addClass("bgposi");
// $(".top").addClass("fixd");
// $(".logo").addClass("maxwidth");
}
}
});
To:
$(window).scroll(function() {
var scroll = $(window).scrollTop();
if (scroll >= 50) {
$(".class").addClass("bgposi");
// $(".top").addClass("fixd");
// $(".logo").addClass("maxwidth");
} else if (scroll <= 50) {
$(".class").removeClass("bgposi");
// $(".top").removeClass("fixd");
// $(".logo").removeClass("maxwidth");
}
});
You could cache some reused selectors (doing the lookup once), like so:
$(window).scroll(function() {
var scroll = $(this).scrollTop();
var $class = $(".class"),
$top = $(".top"),
$logo = $(".logo");
if (scroll >= 50) {
$class.addClass("bgposi");
$top.addClass("fixd");
$logo.addClass("maxwidth");
} else if (scroll <= 50) {
$class.removeClass("bgposi");
$top.removeClass("fixd");
$logo.removeClass("maxwidth");
}
});
$(window).scroll(function() {
var scroll = $(this).scrollTop();
var $class = $(".class");
if (scroll >= 50) {
$class.addClass("bgposi");
} else if (scroll <= 50) {
$class.removeClass("bgposi");
}
});
body {
height: 200vh;
background-color: peachpuff;
}
.class {
position: absolute;
top: 0;
left: 0;
right: 0;
bottom: 20%;
background-color: dodgerblue;
}
.class.bgposi {
background-color: purple;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="class"></div>

How can I make a div stick to the top of the screen once it's been scrolled to?

I would like to create a div, that is situated beneath a block of content but that once the page has been scrolled enough to contact its top boundary, becomes fixed in place and scrolls with the page.
You could use simply css, positioning your element as fixed:
.fixedElement {
background-color: #c0c0c0;
position:fixed;
top:0;
width:100%;
z-index:100;
}
Edit: You should have the element with position absolute, once the scroll offset has reached the element, it should be changed to fixed, and the top position should be set to zero.
You can detect the top scroll offset of the document with the scrollTop function:
$(window).scroll(function(e){
var $el = $('.fixedElement');
var isPositionFixed = ($el.css('position') == 'fixed');
if ($(this).scrollTop() > 200 && !isPositionFixed){
$el.css({'position': 'fixed', 'top': '0px'});
}
if ($(this).scrollTop() < 200 && isPositionFixed){
$el.css({'position': 'static', 'top': '0px'});
}
});
When the scroll offset reached 200, the element will stick to the top of the browser window, because is placed as fixed.
You've seen this example on Google Code's issue page and (only recently) on Stack Overflow's edit page.
CMS's answer doesn't revert the positioning when you scroll back up. Here's the shamelessly stolen code from Stack Overflow:
function moveScroller() {
var $anchor = $("#scroller-anchor");
var $scroller = $('#scroller');
var move = function() {
var st = $(window).scrollTop();
var ot = $anchor.offset().top;
if(st > ot) {
$scroller.css({
position: "fixed",
top: "0px"
});
} else {
$scroller.css({
position: "relative",
top: ""
});
}
};
$(window).scroll(move);
move();
}
<div id="sidebar" style="width:270px;">
<div id="scroller-anchor"></div>
<div id="scroller" style="margin-top:10px; width:270px">
Scroller Scroller Scroller
</div>
</div>
<script type="text/javascript">
$(function() {
moveScroller();
});
</script>
And a simple live demo.
A nascent, script-free alternative is position: sticky, which is supported in Chrome, Firefox, and Safari. See the article on HTML5Rocks and demo, and Mozilla docs.
As of January 2017 and the release of Chrome 56, most browsers in common use support the position: sticky property in CSS.
#thing_to_stick {
position: sticky;
top: 0px;
}
does the trick for me in Firefox and Chrome.
In Safari you still need to use position: -webkit-sticky.
Polyfills are available for Internet Explorer and Edge; https://github.com/wilddeer/stickyfill seems to be a good one.
And here's how without jquery (UPDATE: see other answers where you can now do this with CSS only)
var startProductBarPos=-1;
window.onscroll=function(){
var bar = document.getElementById('nav');
if(startProductBarPos<0)startProductBarPos=findPosY(bar);
if(pageYOffset>startProductBarPos){
bar.style.position='fixed';
bar.style.top=0;
}else{
bar.style.position='relative';
}
};
function findPosY(obj) {
var curtop = 0;
if (typeof (obj.offsetParent) != 'undefined' && obj.offsetParent) {
while (obj.offsetParent) {
curtop += obj.offsetTop;
obj = obj.offsetParent;
}
curtop += obj.offsetTop;
}
else if (obj.y)
curtop += obj.y;
return curtop;
}
* {margin:0;padding:0;}
.nav {
border: 1px red dashed;
background: #00ffff;
text-align:center;
padding: 21px 0;
margin: 0 auto;
z-index:10;
width:100%;
left:0;
right:0;
}
.header {
text-align:center;
padding: 65px 0;
border: 1px red dashed;
}
.content {
padding: 500px 0;
text-align:center;
border: 1px red dashed;
}
.footer {
padding: 100px 0;
text-align:center;
background: #777;
border: 1px red dashed;
}
<header class="header">This is a Header</header>
<div id="nav" class="nav">Main Navigation</div>
<div class="content">Hello World!</div>
<footer class="footer">This is a Footer</footer>
I had the same problem as you and ended up making a jQuery plugin to take care of it. It actually solves all the problems people have listed here, plus it adds a couple of optional features too.
Options
stickyPanelSettings = {
// Use this to set the top margin of the detached panel.
topPadding: 0,
// This class is applied when the panel detaches.
afterDetachCSSClass: "",
// When set to true the space where the panel was is kept open.
savePanelSpace: false,
// Event fires when panel is detached
// function(detachedPanel, panelSpacer){....}
onDetached: null,
// Event fires when panel is reattached
// function(detachedPanel){....}
onReAttached: null,
// Set this using any valid jquery selector to
// set the parent of the sticky panel.
// If set to null then the window object will be used.
parentSelector: null
};
https://github.com/donnyv/sticky-panel
demo: http://htmlpreview.github.io/?https://github.com/donnyv/sticky-panel/blob/master/jquery.stickyPanel/Main.htm
The simplest solution (without js) :
demo
.container {
position: relative;
}
.sticky-div {
position: sticky;
top: 0;
}
<div class="container">
<h1>
relative container & sticky div
</h1>
<div class="sticky-div"> this row is sticky</div>
<div>
content
</div>
</div>
This is how i did it with jquery. This was all cobbled together from various answers on stack overflow. This solution caches the selectors for faster performance and also solves the "jumping" issue when the sticky div becomes sticky.
Check it out on jsfiddle: http://jsfiddle.net/HQS8s/
CSS:
.stick {
position: fixed;
top: 0;
}
JS:
$(document).ready(function() {
// Cache selectors for faster performance.
var $window = $(window),
$mainMenuBar = $('#mainMenuBar'),
$mainMenuBarAnchor = $('#mainMenuBarAnchor');
// Run this on scroll events.
$window.scroll(function() {
var window_top = $window.scrollTop();
var div_top = $mainMenuBarAnchor.offset().top;
if (window_top > div_top) {
// Make the div sticky.
$mainMenuBar.addClass('stick');
$mainMenuBarAnchor.height($mainMenuBar.height());
}
else {
// Unstick the div.
$mainMenuBar.removeClass('stick');
$mainMenuBarAnchor.height(0);
}
});
});
As Josh Lee and Colin 't Hart have said, you could optionally just use position: sticky; top: 0; applying to the div that you want the scrolling at...
Plus, the only thing you will have to do is copy this into the top of your page or format it to fit into an external CSS sheet:
<style>
#sticky_div's_name_here { position: sticky; top: 0; }
</style>
Just replace #sticky_div's_name_here with the name of your div, i.e. if your div was <div id="example"> you would put #example { position: sticky; top: 0; }.
Here is another option:
JAVASCRIPT
var initTopPosition= $('#myElementToStick').offset().top;
$(window).scroll(function(){
if($(window).scrollTop() > initTopPosition)
$('#myElementToStick').css({'position':'fixed','top':'0px'});
else
$('#myElementToStick').css({'position':'absolute','top':initTopPosition+'px'});
});
Your #myElementToStick should start with position:absolute CSS property.
Here's one more version to try for those having issues with the others. It pulls together the techniques discussed in this duplicate question, and generates the required helper DIVs dynamically so no extra HTML is required.
CSS:
.sticky { position:fixed; top:0; }
JQuery:
function make_sticky(id) {
var e = $(id);
var w = $(window);
$('<div/>').insertBefore(id);
$('<div/>').hide().css('height',e.outerHeight()).insertAfter(id);
var n = e.next();
var p = e.prev();
function sticky_relocate() {
var window_top = w.scrollTop();
var div_top = p.offset().top;
if (window_top > div_top) {
e.addClass('sticky');
n.show();
} else {
e.removeClass('sticky');
n.hide();
}
}
w.scroll(sticky_relocate);
sticky_relocate();
}
To make an element sticky, do:
make_sticky('#sticky-elem-id');
When the element becomes sticky, the code manages the position of the remaining content to keep it from jumping into the gap left by the sticky element. It also returns the sticky element to its original non-sticky position when scrolling back above it.
My solution is a little verbose, but it handles variable positioning from the left edge for centered layouts.
// Ensurs that a element (usually a div) stays on the screen
// aElementToStick = The jQuery selector for the element to keep visible
global.makeSticky = function (aElementToStick) {
var $elementToStick = $(aElementToStick);
var top = $elementToStick.offset().top;
var origPosition = $elementToStick.css('position');
function positionFloater(a$Win) {
// Set the original position to allow the browser to adjust the horizontal position
$elementToStick.css('position', origPosition);
// Test how far down the page is scrolled
var scrollTop = a$Win.scrollTop();
// If the page is scrolled passed the top of the element make it stick to the top of the screen
if (top < scrollTop) {
// Get the horizontal position
var left = $elementToStick.offset().left;
// Set the positioning as fixed to hold it's position
$elementToStick.css('position', 'fixed');
// Reuse the horizontal positioning
$elementToStick.css('left', left);
// Hold the element at the top of the screen
$elementToStick.css('top', 0);
}
}
// Perform initial positioning
positionFloater($(window));
// Reposition when the window resizes
$(window).resize(function (e) {
positionFloater($(this));
});
// Reposition when the window scrolls
$(window).scroll(function (e) {
positionFloater($(this));
});
};
Here is an extended version to Josh Lee's answer. If you want the div to be on sidebar to the right, and float within a range (i.e., you need to specify top and bottom anchor positions). It also fixes a bug when you view this on mobile devices (you need to check left scroll position otherwise the div will move off screen).
function moveScroller() {
var move = function() {
var st = $(window).scrollTop();
var sl = $(window).scrollLeft();
var ot = $("#scroller-anchor-top").offset().top;
var ol = $("#scroller-anchor-top").offset().left;
var bt = $("#scroller-anchor-bottom").offset().top;
var s = $("#scroller");
if(st > ot) {
if (st < bt - 280) //280px is the approx. height for the sticky div
{
s.css({
position: "fixed",
top: "0px",
left: ol-sl
});
}
else
{
s.css({
position: "fixed",
top: bt-st-280,
left: ol-sl
});
}
} else {
s.css({
position: "relative",
top: "",
left: ""
});
}
};
$(window).scroll(move);
move();
}
I came across this when searching for the same thing. I know it's an old question but I thought I'd offer a more recent answer.
Scrollorama has a 'pin it' feature which is just what I was looking for.
http://johnpolacek.github.io/scrollorama/
The info provided to answer this other question may be of help to you, Evan:
Check if element is visible after scrolling
You basically want to modify the style of the element to set it to fixed only after having verified that the document.body.scrollTop value is equal to or greater than the top of your element.
The accepted answer works but doesn't move back to previous position if you scroll above it. It is always stuck to the top after being placed there.
$(window).scroll(function(e) {
$el = $('.fixedElement');
if ($(this).scrollTop() > 42 && $el.css('position') != 'fixed') {
$('.fixedElement').css( 'position': 'fixed', 'top': '0px');
} else if ($(this).scrollTop() < 42 && $el.css('position') != 'relative') {
$('.fixedElement').css( 'relative': 'fixed', 'top': '42px');
//this was just my previous position/formating
}
});
jleedev's response whould work, but I wasn't able to get it to work. His example page also didn't work (for me).
You can add 3 extra rows so when the user scroll back to the top, the div will stick on its old place:
Here is the code:
if ($(this).scrollTop() < 200 && $el.css('position') == 'fixed'){
$('.fixedElement').css({'position': 'relative', 'top': '200px'});
}
I have links setup in a div so it is a vertical list of letter and number links.
#links {
float:left;
font-size:9pt;
margin-left:0.5em;
margin-right:1em;
position:fixed;
text-align:center;
width:0.8em;
}
I then setup this handy jQuery function to save the loaded position and then change the position to fixed when scrolling beyond that position.
NOTE: this only works if the links are visible on page load!!
var listposition=false;
jQuery(function(){
try{
///// stick the list links to top of page when scrolling
listposition = jQuery('#links').css({'position': 'static', 'top': '0px'}).position();
console.log(listposition);
$(window).scroll(function(e){
$top = $(this).scrollTop();
$el = jQuery('#links');
//if(typeof(console)!='undefined'){
// console.log(listposition.top,$top);
//}
if ($top > listposition.top && $el.css('position') != 'fixed'){
$el.css({'position': 'fixed', 'top': '0px'});
}
else if ($top < listposition.top && $el.css('position') == 'fixed'){
$el.css({'position': 'static'});
}
});
} catch(e) {
alert('Please vendor admin#mydomain.com (Myvendor JavaScript Issue)');
}
});
In javascript you can do:
var element = document.getElementById("myid");
element.style.position = "fixed";
element.style.top = "0%";
Here's an example that uses jquery-visible plugin: http://jsfiddle.net/711p4em4/.
HTML:
<div class = "wrapper">
<header>Header</header>
<main>
<nav>Stick to top</nav>
Content
</main>
<footer>Footer</footer>
</div>
CSS:
* {
margin: 0;
padding: 0;
}
body {
background-color: #e2e2e2;
}
.wrapper > header,
.wrapper > footer {
font: 20px/2 Sans-Serif;
text-align: center;
background-color: #0040FF;
color: #fff;
}
.wrapper > main {
position: relative;
height: 500px;
background-color: #5e5e5e;
font: 20px/500px Sans-Serif;
color: #fff;
text-align: center;
padding-top: 40px;
}
.wrapper > main > nav {
position: absolute;
top: 0;
left: 0;
right: 0;
font: 20px/2 Sans-Serif;
color: #fff;
text-align: center;
background-color: #FFBF00;
}
.wrapper > main > nav.fixed {
position: fixed;
top: 0;
left: 0;
right: 0;
}
JS (include jquery-visible plugin):
(function($){
/**
* Copyright 2012, Digital Fusion
* Licensed under the MIT license.
* http://teamdf.com/jquery-plugins/license/
*
* #author Sam Sehnert
* #desc A small plugin that checks whether elements are within
* the user visible viewport of a web browser.
* only accounts for vertical position, not horizontal.
*/
var $w = $(window);
$.fn.visible = function(partial,hidden,direction){
if (this.length < 1)
return;
var $t = this.length > 1 ? this.eq(0) : this,
t = $t.get(0),
vpWidth = $w.width(),
vpHeight = $w.height(),
direction = (direction) ? direction : 'both',
clientSize = hidden === true ? t.offsetWidth * t.offsetHeight : true;
if (typeof t.getBoundingClientRect === 'function'){
// Use this native browser method, if available.
var rec = t.getBoundingClientRect(),
tViz = rec.top >= 0 && rec.top < vpHeight,
bViz = rec.bottom > 0 && rec.bottom <= vpHeight,
lViz = rec.left >= 0 && rec.left < vpWidth,
rViz = rec.right > 0 && rec.right <= vpWidth,
vVisible = partial ? tViz || bViz : tViz && bViz,
hVisible = partial ? lViz || rViz : lViz && rViz;
if(direction === 'both')
return clientSize && vVisible && hVisible;
else if(direction === 'vertical')
return clientSize && vVisible;
else if(direction === 'horizontal')
return clientSize && hVisible;
} else {
var viewTop = $w.scrollTop(),
viewBottom = viewTop + vpHeight,
viewLeft = $w.scrollLeft(),
viewRight = viewLeft + vpWidth,
offset = $t.offset(),
_top = offset.top,
_bottom = _top + $t.height(),
_left = offset.left,
_right = _left + $t.width(),
compareTop = partial === true ? _bottom : _top,
compareBottom = partial === true ? _top : _bottom,
compareLeft = partial === true ? _right : _left,
compareRight = partial === true ? _left : _right;
if(direction === 'both')
return !!clientSize && ((compareBottom <= viewBottom) && (compareTop >= viewTop)) && ((compareRight <= viewRight) && (compareLeft >= viewLeft));
else if(direction === 'vertical')
return !!clientSize && ((compareBottom <= viewBottom) && (compareTop >= viewTop));
else if(direction === 'horizontal')
return !!clientSize && ((compareRight <= viewRight) && (compareLeft >= viewLeft));
}
};
})(jQuery);
$(function() {
$(window).scroll(function() {
$(".wrapper > header").visible(true) ?
$(".wrapper > main > nav").removeClass("fixed") :
$(".wrapper > main > nav").addClass("fixed");
});
});
I used some of the work above to create this tech. I improved it a bit and thought I would share my work. Hope this helps.
jsfiddle Code
function scrollErrorMessageToTop() {
var flash_error = jQuery('#flash_error');
var flash_position = flash_error.position();
function lockErrorMessageToTop() {
var place_holder = jQuery("#place_holder");
if (jQuery(this).scrollTop() > flash_position.top && flash_error.attr("position") != "fixed") {
flash_error.css({
'position': 'fixed',
'top': "0px",
"width": flash_error.width(),
"z-index": "1"
});
place_holder.css("display", "");
} else {
flash_error.css('position', '');
place_holder.css("display", "none");
}
}
if (flash_error.length > 0) {
lockErrorMessageToTop();
jQuery("#flash_error").after(jQuery("<div id='place_holder'>"));
var place_holder = jQuery("#place_holder");
place_holder.css({
"height": flash_error.height(),
"display": "none"
});
jQuery(window).scroll(function(e) {
lockErrorMessageToTop();
});
}
}
scrollErrorMessageToTop();​
This is a little bit more dynamic of a way to do the scroll. It does need some work and I will at some point turn this into a pluging but but this is what I came up with after hour of work.
Not an exact solution but a great alternative to consider
this CSS ONLY Top of screen scroll bar. Solved all the problem with ONLY CSS, NO JavaScript, NO JQuery, No Brain work (lol).
Enjoy my fiddle :D all the codes are included in there :)
CSS
#menu {
position: fixed;
height: 60px;
width: 100%;
top: 0;
left: 0;
border-top: 5px solid #a1cb2f;
background: #fff;
-moz-box-shadow: 0 2px 3px 0px rgba(0, 0, 0, 0.16);
-webkit-box-shadow: 0 2px 3px 0px rgba(0, 0, 0, 0.16);
box-shadow: 0 2px 3px 0px rgba(0, 0, 0, 0.16);
z-index: 999999;
}
.w {
width: 900px;
margin: 0 auto;
margin-bottom: 40px;
}<br type="_moz">
Put the content long enough so you can see the effect here :)
Oh, and the reference is in there as well, for the fact he deserve his credit
CSS ONLY Top of screen scroll bar
sticky till the footer hits the div:
function stickyCostSummary() {
var stickySummary = $('.sticky-cost-summary');
var scrollCostSummaryDivPosition = $(window).scrollTop();
var footerHeight = $('#footer').height();
var documentHeight = $(document).height();
var costSummaryHeight = stickySummary.height();
var headerHeight = 83;
var footerMargin = 10;
var scrollHeight = 252;
var footerPosition = $('#footer').offset().top;
if (scrollCostSummaryDivPosition > scrollHeight && scrollCostSummaryDivPosition <= (documentHeight - footerHeight - costSummaryHeight - headerHeight - footerMargin)) {
stickySummary.removeAttr('style');
stickySummary.addClass('fixed');
} else if (scrollCostSummaryDivPosition > (documentHeight - footerHeight - costSummaryHeight - headerHeight - footerMargin)) {
stickySummary.removeClass('fixed');
stickySummary.css({
"position" : "absolute",
"top" : (documentHeight - footerHeight - costSummaryHeight - headerHeight - footerMargin - scrollHeight) + "px"
});
} else {
stickySummary.removeClass('fixed');
stickySummary.css({
"position" : "absolute",
"top" : "0"
});
}
}
$window.scroll(stickyCostSummary);

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