I am making a web page (kind of like those music release pages, here is an example), and I would like certain div's at the bottom not to be shown until the user has scrolled to the bottom of the page, delay a second or two, then pop up. Kind of like a hidden feature thing.
You can also think of it like an infinite scroll, like when you drag down your Instagram feed at the top it refreshes it, and new posts show up. That's the user experience I'm looking for, only in my case it is a "finite scroll", just with some div's hidden by default.
I currently have two implementations of it, neither fully achieves the desired experience. Both used jQuery Slim.
In both implementations, #hidden is the id of my hidden-by-default div, it has style="display: none;" inline, on the div tag.
The first one looks like this:
$(window).scroll(function() {
var x = $(document).height() - $(window).height() - 20;
if( $(window).scrollTop() > x ) {
$("#hidden").delay(1000).show(0);
}
else {
$("#hidden").hide(0);
}
});
The problem with this one is that when the div shows up it changes the document height, so when you get to the bottom of the page it kind of flickers (due to recomputing the document height), and sometimes goes back to being hidden. Really bad user experience.
The second one looks like this:
$(window).scroll(function() {
if( $(window).scrollTop() > 75 ) {
$("#hidden").delay(1000).show(0);
}
else {
$("#hidden").hide(0);
}
});
This one got rid of the flickering problem by keeping the threshold static altogether, slightly better user experience, but not really flexible, in the case that my page gets longer I'll have to set a new threshold for the div to show up.
In neither of the above solutions did the delay(1000) work. The div showed up as soon as the page gets scrolled to the bottom.
Is it possible to make this design work out?
You can try this code:
$(window).on("scroll", function() {
var scrollHeight = $(document).height();
var scrollPosition = $(window).height() + $(window).scrollTop();
if ((scrollHeight - scrollPosition) / scrollHeight === 0) {
$("#hidden").delay(1000).show(0);
}
});
Related
I need to know if the end of a div element is currently visible in the users' browser.
I tried something I saw on the web, but scrollTop() always gave me zero in my Browser. I read something about an issue in Chrome, but I didn't understand quite well.
jQuery(
function($) {
$('#flux').bind('scroll', function() {
if ($(this).scrollTop() + $(this).innerHeight() >= $(this)[0].scrollHeight) {
alert('end reached');
}
})
}
);
My idea is the following:
1- User loads page and sees a Bar (sticky div at bottom visible page) with some information.
2- After scrolling a bit, and reaching the end of a div element, this bar will position there, after the div. This is the bar's original position
I wasn't really able to know when I was at the end of the div element. Eventually I found this code:
if ($(window).scrollTop() >= $('#block-homepagegrid').offset().top + $('#block-homepagegrid').outerHeight() - window.innerHeight) {
$('.hero-special-message').removeClass('hero-special-messege-scrolling');
} else {
$('.hero-special-message').addClass('hero-special-messege-scrolling');
}
});
I see that it's working, but I'm having a bit of trouble understanding what it does.
I know the following:
1. $(window).scrollTop();
this gives me the amount of pixels the user has scrolled, pretty self explanatory.
2. $('#block-homepagegrid').offset().top;
I THINK this is the distance between the start of the page and the start of the div. I know it's the current coordinates, but what is top exactly here?
3. $('#block-homepagegrid').outerHeight();
this gives the height of the element, I know there are 3, like
height(), innerHeight() and outerHeight(), if you want to take into
account border, margin, padding, which is the better to use?
4. window.innerHeight;
I understand this is what the user sees, but I'm having troubles understanding why does it matter for my situation.
Thanks!
You may be interested in the native JavaScript IntersectionObserver API. It automatically figures out what percentage of a given element is visible in the window and triggers callbacks based on that. So then you can do this:
function visibleHandler(entries) {
if (entries[0].intersectionRatio >= 1.0) {
// The whole element is visible!
} else {
// Part of it is scrolled offscreen!
}
}
const observer = new IntersectionObserver(visibleHandler, {threshold: 1.0});
observer.observe(document.getElementById('flux'));
Now, whenever the element with ID flux is 100% in view, it will trigger the visibleHandler. It will also trigger again if it's scrolled back out of view; that's why the function checks the ratio of visibility to see if it just hit 100% or just got reduced from 100%. You could be more fancy and use the observer entry's insersectionRect, which gives you the rectangle containing the visible portion of the element, and use that to determine top/bottom visibility.
I am using Jquery to create an effect that will change things as the user scrolls
$(function() {
var headerPosition = $(".home-header");
$(window)
.scroll(function() {
var scroll = $(window)
.scrollTop();
if (scroll >= 200) {
headerPosition.addClass("home-header-color");
} else if (scroll <= 600) {
headerPosition.removeClass("home-header-color");
}
});
});
This is what i'm using a simple add remove class function that gets triggered on a certain scroll amount.
What I want to do is to make it as a user scrolls once no matter how fast.
This is what I came up with but dose not work well scrolling up.
Codepen
I want it to only appear when you reach the top of the screen when scrolling up. Not on just one scroll up.
I tried combining the two but it didn't work out well.
Problem:
I'm trying to fadeIn and fadeOut div class="audioBox" once the user scrolls past the header. What I have seems to work fine, except for when the page is loaded and I'm already past the 835px height of the header/
Q: What I'm seeing is when I scroll the audioBox quickly fades in and then fades out, despite scroll >= header How do I prevent this from happening?
scripts.js
// If the reader scrolls past header, show audioBox
var scroll = $(window).scrollTop();
var header = $("header").height();
if (scroll >= header) {
$(".audioBox").fadeIn();
} else if (scroll <= header) {
$(".audioBox").fadeOut();
}
I tried implementing what you're describing in jsfiddle at http://jsfiddle.net/3wqfp2ch/1/.
I'd approach it a bit differently, based on the following ideas:
I personally prefer letting CSS take care of visual stuff via classes, and let jQuery take the simple responsibility of controlling when the classes should be added/removed. I think it makes for a better relationship between the two systems and allows each to do their thing better & more neatly.
I didn't see where you were listening for scroll events on the window, which is essential for figuring out whether a user's scroll position is before or after the header, so have included this in my code
I don't think we need multiple if conditions - there's just one question: "Is the scroll position greater than the header height?".
Here's the JS:
var headerHeight = $("header").height();
var audioBox = $('#audioBox');
$(window).on('scroll', function(){
var scrollPosition = $(window).scrollTop();
if (scrollPosition > headerHeight) {
audioBox.addClass('is-visible');
} else {
audioBox.removeClass('is-visible');
}
});
Check out my fiddle at http://jsfiddle.net/3wqfp2ch/1/ for the HTML & CSS that this relates to, and the working demo putting it all together.
I can't test whether this suffers from the same issue regarding you loading at a point already past the header height from jsfiddle unfortunately, but I wouldn't be expecting the behaviour you described using the code above.
Let me know how you get on!
Calling .fadeIn() or .fadeOut() all the time and having an overlap in the conditions might be the problem.
Try this:
// If the reader scrolls past header, show audioBox
var scroll = $(window).scrollTop();
var header = $("header").offset().top + $("header").height(); // should include the header's offset as well
if (scroll >= header) {
$(".audioBox:hidden").fadeIn();
} else if (scroll < header) {
$(".audioBox:visible").fadeOut();
}
I've recently taken over work on a friend's website, here. I want to get the small logo above the description box to only show up once the user has scrolled past (and subsequently hidden) the large header at top, and disappear again if the user scrolls back up past it. I've tried the methods recommended in these other posts here and here, which seem like the same basic idea but I can't get any of them to work.
I'm new to anything and everything scripting (which I'm entirely sure is the biggest problem here, I know.) So any help is appreciated as what I'm apparently doing wrong.
Start by giving the <div class="fixeddiv"> a style="display: none". Then add the following (since you're already using jQuery):
$(document).ready(function () {
var contentOffset = getOffset();
function getOffset() {
var allOffsets = $("div#content").offset();
return allOffsets.top;
}
$(window).resize(function () {
contentOffset = getOffset();
});
$(window).scroll(function () {
var windowTop = $(window).scrollTop();
if (windowTop > contentOffset) {
$("div.fixeddiv").show();
} else {
$("div.fixeddiv").hide();
}
});
});
Here's what this code does. When the document is done loading, it gets the number of pixels that the "content" div is from the top of the document (offset). It does this again any time the window is resized. Then, when someone scrolls up or down, it gets the number of pixels that are already hidden above the scroll (scrollTop). If the number of hidden pixels is greater than the offset of the #content div from the top of the window, that means we've scrolled past the top of the content div and should show the icon. Otherwise, we should hide the icon.
I was wondering how sites like Facebook, with their timeline feature, float a certain element (usually a menu bar, or sometimes a social plugin, etc) when the user has scrolled past a point such that the top of the element is off the screen, etc.
This could be seen as a more general JavaScript (jQuery?) event firing when the user has scrolled to a certain element, or scrolled down a certain number of pixels.
Obviously it would require toggling the CSS property from:
#foo { position: relative; }
to
#foo { position: fixed; }
Or with jQuery, something like:
$('#foo').css('position', 'fixed');
Another way I have seen this implemented is with blogs, where a popup will be called when you reach the bottom, or near the bottom of a page. My question is, what is firing that code, and could you link or provide some syntax/ semantics/ examples?
Edit: I'm seeing some great JS variants coming up, but as I am using jQuery, I think the plugin mentioned will do just nicely.
Take a look at this jsfiddle: http://jsfiddle.net/remibreton/RWJhM/2/
In this example, I'm using document.onscroll = function(){ //Scroll event } to detect a scroll event on the document.
I'm then calculating the percentage of the page scrolled based on it's height. (document.body.scrollTop * 100 / (document.body.clientHeight - document.documentElement.clientHeight)).
document.body.scrollTop being the number of pixels scrolled from the top, document.body.clientHeight being the height of the entire document and document.documentElement.clientHeight being the visible portion of the document, a.k.a. the viewport.
Then you can compare this value to a target percentage, an execute JavaScript. if(currentPercentage > targetPercentage)...
Here's the whole thing:
document.onscroll = function(){
var targetPercentage = 80;
var currentPercentage = (document.body.scrollTop * 100 / (document.body.clientHeight - document.documentElement.clientHeight));
console.log(currentPercentage);
if(currentPercentage > targetPercentage){
document.getElementById('pop').style.display = 'block';
// Scrolled more than 80%
} else {
document.getElementById('pop').style.display = 'none';
// Scrolled less than 80%
}
}
If you prefer jQuery, here is the same example translated into everybody's favorite library: http://jsfiddle.net/remibreton/8NVS6/1/
$(document).on('scroll', function(){
var targetPercentage = 80;
var currentPercentage = $(document).scrollTop() * 100 / ($(document).height() - $(window).height());
if(currentPercentage > targetPercentage){
$('#pop').css({display:'block'});
//Scrolled more than 80%
} else {
$('#pop').css({display:'none'});
//Scrolled less than 80%
}
});
An idea would be to handle the window.scroll event and determine if the user has scrolled to the bottom of the page. Here is an example:
http://chrissilich.com/blog/load-more-content-as-the-user-reaches-the-bottom-of-your-page-with-jquery/
Hope it helps!
There is a jquery plugin that might help you in the right direction.
http://imakewebthings.com/jquery-waypoints/
I just answered basically the same question here. In that case it was a table and its header, and the basic idea is like this:
function placeHeader(){
var $table = $('#table');
var $header = $('#header');
if ($table.offset().top <= $(window).scrollTop()) {
$header.offset({top: $(window).scrollTop()});
} else {
$header.offset({top: $table.offset().top});
}
}
$(window).scroll(placeHeader);
Here's a demo.
Quoting myself:
In other words, if the top of the table is above the scrollTop, then
position the header at scrollTop, otherwise put it back at the top of
the table. Depending on the contents of the rest of the site, you
might also need to check if you have scrolled all the way past the
table, since then you don't want the header to stay visible.
To answer your question directly, it is triggered by checking the scrollTop against either the position of an element, or the height of the document minus the height of the viewport (for the scrolled to bottom use case). This check is done every time the scroll event is fired (bound using $(window).scroll(...)).