Javascript Scrolling - javascript

What I'm trying to do with javascript is:
Once you scroll so far down the page, change the position of #sidebar-box-fixed from position: relative; to position: fixed;. Change back to position: relative; once you scroll back up.
What would be the easiest way to do this?

You could try something in this direction:
$(document).ready(function() {
var gap = 100;
$(window).on('scroll', function(){
var position = $(window).scrollTop() > gap ? 'fixed' : 'relative';
$("#sidebar-box-fixed").css('position', position);
});
});

Related

How to implement auto fixing a div like https://www.yahoo.com

In Yahoo website, when scroll down, a blue part is fixed to the top, while if not scroll down, the blue part is not fixed.
How to implement this ?
May I try onScroll function?
I use inspect element and, apperantly it changes class when that "blue part" is not in view,
so what it is doing (I guess) is changing the classes while it is in view and not in view, you can find if a div is in view and then change accordingly, "onscroll" is a great idea
Use $(window).scroll(function() on the part which you want to be fixed.
Fiddle Demo : Demo
$(window).scroll(function(){
if ($(window).scrollTop() >= 100) {
$('.sticky-header').addClass('fixed');
}
else {
$('.sticky-header').removeClass('fixed');
}
});
If you want to apply the fixed part to the header replace the class name in the $(window).scroll(function(){}): function.
Example for fixed Header while scrolling : Demo-2
You can make it fixed just with css.
<div id="myHeader">Header stuff</div>
#myHeader {
position: fixed;
top: 0;
width: 100%;
z-index: 1000;
}
Yes, you need to bind to win scroll like this:
var element = $(YOURTOPELEMENT)
$(window).scroll(function () {
var scrollTop = $(window).scrollTop();
if (scrollTop > element.offset().top) {
element.css({
position: "fixed",
top: 0
})
} else {
element.css({
position: "relative"
})
}
})

Javascript smooth scroll without jumping?

I have a script where I once I reach a specific point of the screen the div starts to scroll with the body by adding a fixed position, but it is not smooth and looks horrible. I have not been able to understand if I can add a pageoffset instead of adding a fixed class which causes the div to slightly jump instead of just picking up from where it is.
window.onload = function ()
{
var scrolledElement = document.getElementById('ID');
var top = scrolledElement.offsetTop;
var listener = function ()
{
var y = scrolledElement.scrollTop || scrolledElement.scrollTop || window.pageYOffset;
if (y >= top)
{
scrolledElement.classList.add('fixed');
} else {
scrolledElement.classList.remove('fixed');
}
};
window.addEventListener('scroll', listener, false);
}
but as I said, whenever the body scroll reaches the ID div it just jumps and adds the fixed css which is..
#ID.fixed {
position: fixed;
top:0;
width: 336px;
margin: 0px auto;
margin-top: 15px;
}
I can't understand if by adding offsettop to it instead of css it would make it not jump?

Sidebar that does't scroll more than its contents

I have a page with long content on it. Together with that there is a sidebar which has less content and at the moment if you continue scrolling down, at some point there will be just whitespace in a sidebar.
So what I tried to do is once sidebar reaches end of its content, height give it fixed position, but while there are still things to scroll give it static position.
So I've got
$(window).scroll(function () {
var y = $(window).scrollTop();
var x = $(window).scrollTop() + $(window).height();
var s = $('#sidebar').height();
if (x > s) {
$('#sidebar').css({
'position': 'fixed',
'bottom': '0'
});
}
if (x < s) {
$('#sidebar').css({
'position': 'static'
});
}
});
This kinda works. It starts with static position, but when I scroll in any direction it changes to fixed. However I want it to remain static while there is something to scroll through (in upwards and downwards directions)
EDIT Basically it should work like this: http://jsfiddle.net/cJGVJ/12/ but without the shadow effect.
Give HTML and BODY height: 100%;
html, body{
height: 100%;
}
#sidebar{
position: absolute;
bottom: 0px;
}

Change Div Y Position with mouse wheel and sidebar

I need that when I scroll down or up with mouse wheel or sidebar my div change incrementally the Y position (for example 50px up or down ). I need this in Javascript/Jquery.
I Try this code, but only works for scrolling down(The Scrolling Down and Up Function is working well, only the animate part is working wrong):
UPDATE:
var sidebarScrollTop = 0;
$(document).ready(function() {
sidebarScrollTop = $("body").offset();
$(window).scroll(function ()
{
var docScrollTop = $('body,html').scrollTop();
if(docScrollTop > sidebarScrollTop.top)
{
$("#legend").stop().animate({ marginTop: "+=50px",}, 'slow', "easeOutCirc" );
}
else
{
$("#legend").stop().animate({ marginTop: "-=50px",}, 'slow', "easeOutCirc" );
}
});
});
$(window).resize(function()
{
sidebarScrollTop = $("#legend").offset().top;
});
$(document).resize(function()
{
sidebarScrollTop = $("#legend").offset().top;
});
Thanks
You can use
$(window).scroll(function() {
// Your scroll code here
});
to grab whenever the user is scrolling on the page.
Next you want to change the div's y-value.
If the div is positioned absolute, this is just changing its top-value.
$('my-div').top = original-top-value + $(window).pageYOffset;
I believe you need is to keep the div always showing even when user scrolls down. If that is the case then it can be done with only CSS:
div {
position: fixed;
z-index: 100;
top: 100px;
left: 100px;
}
The values of z-index, top and left are dummy values. Change em with your ones.
UPDATE:
Since CSS Solution won't work for you, here is a working example writter in JS: http://jsfiddle.net/qCtt5/

Position fixed related parent container

I need solution to emulate fixed position, but relative parent div, not whole viewport. JS solutions are laggy. I need fixed related parent container, because if window has small height, div with fixed position enters into footer zone.
Example
Another approach re your update.
Try giving the fixed div z-index: 10;
And the footer div position: relative; z-index: 11
That should make the footer overlap the fixed div.
then it's not an issue of position:fixed, maybe you could just define a min-height to your body (or on the main wrapper if any) to avoid the short page problem
I have combined css and js:
$(document).ready(function () {
var $sidebar = $(".register-box"),
$window = $(window),
$content = $("#content"),
docHeight = $(document).height();
var entered = false;
$window.scroll(function () {
if ($window.height() < 795 && docHeight - $window.scrollTop() < 785) {
entered = true;
var pos = $sidebar.offset();
$sidebar.css('position', 'absolute').css('top', ($content.height() - ($sidebar.height() + 40)) + 'px');
}
else {
if (entered) {
entered = false;
$sidebar.css({
top: "",
left: "",
position: "fixed"
});
}
}
});
});
Code is not final, and numbers are hard coded, but it works, smooth enough.

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