How to create a website with 'infinite' scrolling space? - javascript

I have an idea for a website but I am not yet sure on how to achieve the desired result. The end product would be a website where a series of visible connected nodes are generated based on data that comes back from a database.
The first concern is that I will need the website to accommodate any generated content which could span in any direction.
So does anyone know how to achieve an 'infinite' scrolling website? I have seen this kind of thing for online idea boards where the user can move their mouse in any direction and the page begins to scroll, with the page expanding seemingly infinitely.

You can try something like this:
// Fetch variables
var scrollTop = $(document).scrollTop();
var windowHeight = $(window).height();
var bodyHeight = $(document).height() - windowHeight;
var scrollPercentage = (scrollTop / bodyHeight);
// if the scroll is more than 90% from the top, load more content.
if(scrollPercentage > 0.9) {
// Load content
}

The first thing that strikes my mind on the concept of infinite scrolling is Facebook! The page at qnimate might be the code you are looking for -
qnimate.com/facebook-style-infinite-scroll
For infinity scrolling in either direction you will have to tweak the code to include window.pageXOffset
Other links that I would recommend checking out is -
sitepoint.com/jquery-infinite-scrolling-demos/
tutsplus.com/articles/vertical-and-horizontal-scrolling-with-fullpagejs

Related

What's the most accurate way of measuring scroll?

I'm making a slide scrolling page, and I'm trying to have it scroll like you're pulling a notecard up and with the next one right behind it.
To do this, I'm making them all fixed, and then moving their "top" position based off of scroll. But then I also need to make the body the size of the panel.
It's hard to describe what I'm doing, so here's the demo: https://codepen.io/NotDan/pen/vzraJE
Here's the particular piece of code that's causing my problem:
//what's going on here?
$(window).scroll(function(){
var panelNum = parseInt($(window).scrollTop()/$(window).height());//detemines panel number
var pixelMovement = ($(window).scrollTop())-(panelNum*$(".panel").height()); determines how many pixels to move the panel by
$('body').find(".panel:eq("+panelNum+")").css("top", -1*pixelMovement);
});
The problem is when the user scrolls quickly, the top position is not set accurately and there's some overhang. Again, hard to explain, but if you jump to the demo and scroll quickly you'll see what I mean.
Is there a more precise way of measuring scroll? Or is there a better way to do what I'm trying to? I've tried scrollmagic, and its "section wipe" feature is really close, but they bring the previous one up rather than move the current one up.
I tried making a condition to determine the panel number and everything started working.
var panelNum = 0;
var pixelMovement = 0;
$(window).scroll(function () {
pixelMovement = $(window).scrollTop() - panelNum * $(".panel").height(); // determines how many pixels to move the panel by
$("body")
.find(".panel:eq(" + panelNum + ")")
.css("top", -1 * pixelMovement);
if (Math.abs(pixelMovement) >= $(window).height()) {
panelNum++;
} else if (pixelMovement <= 0) {
panelNum--;
}
});
Here's the working demo: https://codepen.io/NotDan/pen/RYJeZq

Hide a div until scrolled to the bottom of the page

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);
}
});

jQuery's scrollTop() behaving strange on Android browsers including Chrome

I'm having trouble with an animated scrollbar. The intended behaviour should be on clicking the nav-button, scroll with ease to the end of the page(and a little break near the end).
Now the problem on PC works perfect. On android device (I tried my phone), the scrollTop value and the ($(document.body).height() - $(window).height()) do not match. There is exactly 55px less with the scrollTop thus acting all sorts of strange... Also sometimes it works sometimes it doesn't. I've figured it has something to do with the browser bar collapsing and upsetting the value...but i can't figure it out.
I've tried the following: initializing the variables on scroll event, i've tried vanilla js that didn't work. Need help :) for reference http://www.developer.morningmood.org , also i've printed out the values on bottom of the page if it helps. Here's the code.
contactF = Math.floor($(document.body).height() - $(window).height());
$("#cont").click(function(){
if ($(document).scrollTop() < contactF && flagScroll==true){ //flag stops other buttons from beying pushed
flagScroll = false;
var inter = setInterval(function(){
var doc = $(document).scrollTop();
if (doc == contactF){ // this is the final desired position
clearInterval(inter);
flagScroll = true;
pix = 10; //pixels to jump
return;
}
if (doc >= contactF-50){ // this is a break on aproach
pix = 1;
}
$(document).scrollTop(doc + pix);
}, 10);
}
})
EDIT: also to find the bug, you nedd to scroll from the top of the page all the way to the bottom, if from the top of the page you just push the contact button it works. but if you scroll it doesn't, it upsets the value...
Had the same exact problem and spent a whole day to figure it out.
You are right about the address bar collapse on Android chrome messing it up. Turns out the jQuery function $(window).height() always reports the viewport height that is before the address bar collapses. To get the correct value, use window.innerHeight instead. You can find more information about URL bar resizing here https://developers.google.com/web/updates/2016/12/url-bar-resizing
You can also find people asking similar questions regarding the safari address bar auto-hide, the solutions are similar. Mobile Safari $(window).height() URL bar discrepancy

Fade in div once user scrolls past element

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();
}

Freeze element (position:fixed) for specific scroll range

I'm working on this site (http://styleguide.co/medhelp/) that has 5 sections. For one of the sections (Styles), I've got a sidenav I'm trying to get to stick in the visible frame only as long as users are scrolling in that section.
Here's what I've done thus far - I'm telling the section title & sidenav to stick after the top of the section has begun:
$(window).scroll(function(event) {
var sw = $('.fixed'),
pg = $('.styles'),
diff = pg[0].offsetTop - window.pageYOffset;
if (diff < 80 ) {
$('.fixed').css('position', 'fixed');
$('.fixed').css('top', '160px');
$('.styles').css('position', 'fixed');
$('.styles').css('top', '70px');
}
else {
$('.fixed').css('position', 'relative');
$('.fixed').css('top', '0px');
$('.styles').css('position', 'relative');
$('.styles').css('top', '0px');
}
});
I can't seem to figure out a good way to make the section title "Style" and the sidenav appear/disappear while I scroll to/from that section. Any advice? What could I do better? A simple solution demo in jsfiddle would really help!
Please click on this link & scroll down/up to know what I'm referring to: http://styleguide.co/medhelp/
I'm not going to give you a fiddle, but you need to determine when the next section would stick based on its offset from the top. At the moment what you are doing is:
// if difference top and element < 80 -> fix to top, else position is relative
First of all this means the condition will never be undone. What you need to do in order to continue is:
// once next contact section comes into screen
//(offset from the top of the screen <= screen height), give
var winHeight = $(window).height();
var calcTop = 80 - (winHeight - (winHeight - $('#nextSelector').offset().top);
$('.fixed').css('top', calcTop);
This will give the illusion of your text scrolling up as the new section comes up. I hope this helps. Also, when scrolling back up it doesn't re-stick, but you probably are aware of that.

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