I was wondering how to add extra 'top' .offset() to this div;
mapstick
I think its something to do startPosition?? I thought I could get away with changing it in CSS but this just broke the function of the div unsticking at a certain height.
I tried in the CSS to make the top px '!important' on the div. This is what broke the if/else statement as it messed up what the actual top of the div and the script didn't realise this it looks like.
var navWrap = $('#navWrap'),
nav = $('#mapstick'),
startPosition = navWrap.offset().top,
stopPosition = $('#stopHere').offset().top - nav.outerHeight();
$(document).scroll(function () {
//stick nav to top of page
var y = $(this).scrollTop()
if (y > startPosition) {
nav.addClass('sticky');
if (y > stopPosition) {
nav.css('top', stopPosition - y);
} else {
nav.css('top', 0);
}
} else {
nav.removeClass('sticky');
}
});
I just need an extra 70px on the top of the div so it can be fully visible.
I have also looked at using this;
.offset({ top: 70 });
I think I used this wrong as this just messed things up.
Turns out I can just amend another class to a child div to have the effect that I am wanting. So I have just added an extra 'addClass' to the if statement and it seems to have done the trick.
This is the script that I have now;
var navWrap = $('#navWrap'),
nav = $('#mapstick'),
maptop = $('#map')
startPosition = navWrap.offset().top ,
stopPosition = $('#stopHere').offset().top - nav.outerHeight();
$(document).scroll(function () {
//stick nav to top of page
var y = $(this).scrollTop()
if (y > startPosition) {
nav.addClass('sticky'),
maptop.addClass('maptop');
if (y > stopPosition) {
nav.css('top', stopPosition - y);
} else {
nav.css('top', 0);
}
} else {
nav.removeClass('sticky'),
maptop.addClass('maptop');
}
});
I have added in the 'maptop' to the if statement which is working. I don't know if this is the best way to do it but it is working and I am fine with that lol
I tried a lot of solutions but I cant make the divs stop following the scroll at the footer.
Here is my code to make the divs follow the scroll (colderecha and colizquierda are my divs that follow the scroll):
$(document).ready(function () {
var top = $('#colizquierda').offset().top - parseFloat($('#colizquierda').css('marginTop').replace(/auto/, 0));
$(window).scroll(function (event) {
var y = $(this).scrollTop();
//if y > top, it means that if we scroll down any more, parts of our element will be outside the viewport
//so we move the element down so that it remains in view.
if (y >= top) {
var difference = y - top;
$('#colizquierda').css("top",difference);
}
});
});
$(document).ready(function () {
var top = $('#colderecha').offset().top - parseFloat($('#colderecha').css('marginTop').replace(/auto/, 0));
$(window).scroll(function (event) {
var y = $(this).scrollTop();
//if y > top, it means that if we scroll down any more, parts of our element will be outside the viewport
//so we move the element down so that it remains in view.
if (y >= top) {
var difference = y - top;
$('#colderecha').css("top",difference);
}
});
});
What I have tried:
$(document).scroll(function() {
checkOffset();
});
function checkOffset() {
if ($('#colizquierda').offset().top + $('#colizquierda').height() >= $('#footer').offset().top - 10)
$('#colizquierda').css('position', 'absolute');
if ($(document).scrollTop() + window.innerHeight < $('#footer').offset().top)
$('#colizquierda').css('position', 'fixed');
if ($('#colderecha').offset().top + $('#colderecha').height() >= $('#footer').offset().top - 10)
$('#colderecha').css('position', 'absolute');
if($(document).scrollTop() + window.innerHeight < $('#footer').offset().top)
$('#colderecha').css('position', 'fixed');
}
Lets say we have a long scrollable page, and a separate side block, which is shorter than page, but longer than screen height.
I'm trying to make the sidebar always inside the screen by one of it's ends.
When scrolling down, sidebar scrolled until fixes with it's bottom to the bottom of the screen:
Then if you scroll upwards, it will scroll until fixed with top:
So sidebar will never leave the screen.
It is simmilar to bootstrap affix, but with scroll ability.
Seems to be a common feature, saw few sites with this behavior, suprised I couldn't find ready implementation.
I just can't make it right, always find new bugs in unusual situations.
Maybe there is ready solution in some library?
Today I realised I don't need "fixed" positon and can update offset on each scroll.
Here is my code if anyone will search for the same question.
html:
<div id="screen">
<div id="page">
</div>
<div id="sidebar">
</div>
</div>
js:
var margin = 0;
var sidebarIsFixed = false;
var lastScroll = 0;
var topOffset = 0;
var sidebar = document.getElementById('sidebar');
var screen = document.getElementById('screen');
var yPos = undefined;
function OnBodyScroll() {
if (yPos == undefined) {
yPos = 0;
var parent = sidebar.offsetParent;
while (parent && parent != screen) {
yPos += parent.offsetTop;
parent = parent.offsetParent;
}
margin = sidebar.offsetTop;
topOffset = margin;
}
var windowHeight = screen.clientHeight;
var barHeight = sidebar.clientHeight;
var scroll = screen.scrollTop;
if (scroll >= lastScroll) {
if (scroll + windowHeight > yPos + topOffset + barHeight + margin) {
topOffset = scroll -yPos + windowHeight - barHeight - margin;
sidebar.style.marginTop = topOffset + "px";
}
} else {
if (scroll < yPos + topOffset - margin) {
topOffset = scroll - yPos + margin;
if (topOffset < margin) {
topOffset = margin;
}
sidebar.style.marginTop = topOffset + "px";
}
}
lastScroll = scroll;
}
screen.onscroll = OnBodyScroll;
OnBodyScroll();
http://jsfiddle.net/ilyad/da543f40/3/
Can anyone help me pinpoint the issue with my script please?
$(function () {
var top = $('#sidebar').offset().top - parseFloat($('#sidebar').css('marginTop').replace(/auto/, 0));
var footTop = $('#footer').offset().top - parseFloat($('#footer').css('marginTop').replace(/auto/, 0));
var maxY = footTop - $('#sidebar').outerHeight();
$(window).scroll(function (evt) {
var y = $(this).scrollTop();
if (y > 100) {
if (y < maxY) {
$('#sidebar').addClass('stickyside').removeAttr('style');
} else {
$('#sidebar').removeClass('stickyside').css({
position: 'absolute',
top: (maxY - top) + 'px'
});
}
} else {
$('#sidebar').removeClass('stickyside');
}
});
});
Live site here - https://tregothnan.co.uk/tea-herbal-infusions/
Sticky sidenav is spilling over the footer div and no matter what I try I can't get it to work. It works fine in my jsfiddle prototype.
The problem is that you are forgetting the margin-top of your sidebar in your calculation:
var maxY = footTop - $('#sidebar').outerHeight() - 68;
In your Prototype JSFiddle the sidebar just happened to have no margin-top.
On a sidenote: you may want to cache your selectors to improve performance. If you use the same selector more than once, for example $("#sidebar"), put it in a variable:var sidebar = $("#sidebar");.
Ok - many thanks #dark-ashelin
ended up with this - bit of a hack but it works.
$(function () {
var sidebar = $("#sidebar");
var top = $('#sidebar').offset().top - parseFloat($('#sidebar').css('marginTop').replace(/auto/, 0));
var footTop = $('#footer').offset().top - parseFloat($('#footer').css('marginTop').replace(/auto/, 0))-60;
var maxY = footTop - $('#sidebar').outerHeight() - 85;
$(window).scroll(function (evt) {
var y = $(this).scrollTop();
if (y > 100) {
if (y < maxY) {
$('#sidebar').addClass('stickyside').removeAttr('style');
} else {
$('#sidebar').removeClass('stickyside').css({
position: 'absolute',
top: (maxY + 50) + 'px'
});
}
} else {
$('#sidebar').removeClass('stickyside');
}
});
});
I need to retrieve the visible height of a div within a scrollable area. I consider myself pretty decent with jQuery, but this is completely throwing me off.
Let's say I've got a red div within a black wrapper:
In the graphic above, the jQuery function would return 248, the visible portion of the div.
Once the user scrolls past the top of the div, as in the above graphic, it would report 296.
Now, once the user has scrolled past the div, it would again report 248.
Obviously my numbers aren't going to be as consistent and clear as they are in this demo, or I'd just hard code for those numbers.
I have a bit of a theory:
Get the height of the window
Get the height of the div
Get the initial offset of the div from the top of the window
Get the offset as the user scrolls.
If the offset is positive, it means the top of the div is still visible.
if it's negative, the top of the div has been eclipsed by the window. At this point, the div could either be taking up the whole height of the window, or the bottom of the div could be showing
If the bottom of the div is showing, figure out the gap between it and the bottom of the window.
It seems pretty simple, but I just can't wrap my head around it. I'll take another crack tomorrow morning; I just figured some of you geniuses might be able to help.
Thanks!
UPDATE: I figured this out on my own, but looks like one of the answers below is more elegant, so I'll be using that instead. For the curious, here's what I came up with:
$(document).ready(function() {
var windowHeight = $(window).height();
var overviewHeight = $("#overview").height();
var overviewStaticTop = $("#overview").offset().top;
var overviewScrollTop = overviewStaticTop - $(window).scrollTop();
var overviewStaticBottom = overviewStaticTop + $("#overview").height();
var overviewScrollBottom = windowHeight - (overviewStaticBottom - $(window).scrollTop());
var visibleArea;
if ((overviewHeight + overviewScrollTop) < windowHeight) {
// alert("bottom is showing!");
visibleArea = windowHeight - overviewScrollBottom;
// alert(visibleArea);
} else {
if (overviewScrollTop < 0) {
// alert("is full height");
visibleArea = windowHeight;
// alert(visibleArea);
} else {
// alert("top is showing");
visibleArea = windowHeight - overviewScrollTop;
// alert(visibleArea);
}
}
});
Calculate the amount of px an element (height) is in viewport
Fiddle demo
This tiny function will return the amount of px an element is visible in the (vertical) Viewport:
function inViewport($el) {
var elH = $el.outerHeight(),
H = $(window).height(),
r = $el[0].getBoundingClientRect(), t=r.top, b=r.bottom;
return Math.max(0, t>0? Math.min(elH, H-t) : Math.min(b, H));
}
Use like:
$(window).on("scroll resize", function(){
console.log( inViewport($('#elementID')) ); // n px in viewport
});
that's it.
jQuery .inViewport() Plugin
jsFiddle demo
from the above you can extract the logic and create a plugin like this one:
/**
* inViewport jQuery plugin by Roko C.B.
* http://stackoverflow.com/a/26831113/383904
* Returns a callback function with an argument holding
* the current amount of px an element is visible in viewport
* (The min returned value is 0 (element outside of viewport)
*/
;(function($, win) {
$.fn.inViewport = function(cb) {
return this.each(function(i,el) {
function visPx(){
var elH = $(el).outerHeight(),
H = $(win).height(),
r = el.getBoundingClientRect(), t=r.top, b=r.bottom;
return cb.call(el, Math.max(0, t>0? Math.min(elH, H-t) : Math.min(b, H)));
}
visPx();
$(win).on("resize scroll", visPx);
});
};
}(jQuery, window));
Use like:
$("selector").inViewport(function(px) {
console.log( px ); // `px` represents the amount of visible height
if(px > 0) {
// do this if element enters the viewport // px > 0
}else{
// do that if element exits the viewport // px = 0
}
}); // Here you can chain other jQuery methods to your selector
your selectors will dynamically listen to window scroll and resize but also return the initial value on DOM ready trough the first callback function argument px.
Here is a quick and dirty concept. It basically compares the offset().top of the element to the top of the window, and the offset().top + height() to the bottom of the window:
function getVisible() {
var $el = $('#foo'),
scrollTop = $(this).scrollTop(),
scrollBot = scrollTop + $(this).height(),
elTop = $el.offset().top,
elBottom = elTop + $el.outerHeight(),
visibleTop = elTop < scrollTop ? scrollTop : elTop,
visibleBottom = elBottom > scrollBot ? scrollBot : elBottom;
$('#notification').text(`Visible height of div: ${visibleBottom - visibleTop}px`);
}
$(window).on('scroll resize', getVisible).trigger('scroll');
html,
body {
margin: 100px 0;
}
#foo {
height: 1000px;
background-color: #C00;
width: 200px;
margin: 0 auto;
}
#notification {
position: fixed;
top: 0;
left: 0;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.6.0/jquery.min.js"></script>
<div id="foo"></div>
<div id="notification"></div>
The logic can be made more succinct if necessary, I've just declared separate variables for this example to make the calculation as clear as I can.
Here is a version of Rory's approach above, except written to function as a jQuery plugin. It may have more general applicability in that format. Great answer, Rory - thanks!
$.fn.visibleHeight = function() {
var elBottom, elTop, scrollBot, scrollTop, visibleBottom, visibleTop;
scrollTop = $(window).scrollTop();
scrollBot = scrollTop + $(window).height();
elTop = this.offset().top;
elBottom = elTop + this.outerHeight();
visibleTop = elTop < scrollTop ? scrollTop : elTop;
visibleBottom = elBottom > scrollBot ? scrollBot : elBottom;
return visibleBottom - visibleTop
}
Can be called with the following:
$("#myDiv").visibleHeight();
jsFiddle
Here is the improved code for jquery function visibleHeight: $("#myDiv").visibleHeight();
$.fn.visibleHeight = function() {
var elBottom, elTop, scrollBot, scrollTop, visibleBottom, visibleTop, height;
scrollTop = $(window).scrollTop();
scrollBot = scrollTop + $(window).height();
elTop = this.offset().top;
elBottom = elTop + this.outerHeight();
visibleTop = elTop < scrollTop ? scrollTop : elTop;
visibleBottom = elBottom > scrollBot ? scrollBot : elBottom;
height = visibleBottom - visibleTop;
return height > 0 ? height : 0;
}