Develop Reference

image slides vertical scroll with jquery or javascript

I have 5 images and I want to slide those images when we hit the arrow up or down with keyboard button or when we move the scroll bar up or down
For reference:www.webflow.com please just check it from the link. when you will scroll down to the Buil Custom section on the page. you will see the slider and its working with when you hit the arrrow button up and down from keyboard or when you move down or up with scroll bar.

You can use https://api.jquery.com/scrollleft/ to scroll horizontal on an element.
Example: $( "div.slider" ).scrollLeft( 300 );
You will have to first compute the width of each element of your slideshow and scroll exactly that much each time.
You can do this on arrow keys with an event handler: Detecting arrow key presses in JavaScript
The reference you linked shows changes in your page based on the scroll position, reading js: change style based in scroll position might give you hints on where to start there.

fullpage.js - add css class to header when scrolling inside a section

I am using fullpage.js
https://github.com/alvarotrigo/fullPage.js/
on a frontpage of a website and it´s working fine so far.
I have 4 Sections.
The first section has more content than the height of the browser window, so there is the need to scroll inside that section.
I have added the scrollbar and it works with the scrollbar and by using the mousewheel.
Now my problem.
I have a sticky header which I want to reduce in height as soon as there is any scrolling down inside this section (and increase in height as soon as I scroll back up to the top).
So I would like to add the css class "sticky" to the "header" when using the scrollbar of the fullpage.js or the mousewheel so that I can format the header with the class "sticky" differently with css.
Unfortunately the "scroll-Events" doesn´t work here, as already mentioned here:
FullPage.JS Scrolling
I tried the following
$(function(){
window.addEventListener("wheel", function() {
$(document).ready(function(){
var scrollclass = $('.slimScrollBar').position();
if(scrollclass.top > 0){
$('header').addClass('sticky');
}
else{
$('header').removeClass('sticky');
}
});
});})
This kind of works, however the sticky class is not added by the first use of the mousewheel (it´s added by the "second turn of the mousewheel") and is not beeing removed when scrolling back to the top, I need to turn the wheel an additional time after scrolling back to the top to have the sticky class removed again.
If I change the if-statement to >= 0 it works on the first turn of the mousewheel but then I don´t get the class removed when scrolling back to the top.
The second issue is, that this only works by using the mousewheel of course, and not by dragging the scrollbar created by fullpage.js
Any ideas or hints how to solve this?
Thanks
John

you could use the "afterLoad" method, as noted in fullPage.JS's documentation:
https://github.com/alvarotrigo/fullPage.js#afterload-anchorlink-index

Maintaining scroll position after height of body is changed

I am working on a page that has two states: edit mode and normal mode. The user switches between these states by clicking on a toggle button. Triggering edit mode adds more elements to the page (buttons, etc) and thus forces the body element to increase its height.
My issue arises when a user has scrolled down the page and then triggers edit mode - since the page's height has now increased, their current scroll position is lost. I have been trying to find a way through which I can calculate what the new scrollTop should be, but have not been successful.
I've got a jsFiddle as an example of my issue. It automatically scrolls to the third "entry", to simulate a user having scrolled down that far. Clicking the "trigger change" button in the top right hand corner will add more elements to the page, and the scroll position of having the third entry at the top of the page is lost.
I am aware that I could just redo $('body').scrollTop($('.entry:nth-child(3)').offset().top); after the new contents have been added, but I want the scroll position to be remembered for no matter where the user has scrolled to on the page.
http://jsfiddle.net/Jn8wq/2/
Any help is greatly appreciated!

Check this fiddle.
http://jsfiddle.net/Jn8wq/4/
I added this
var tempScrollTop = $(window).scrollTop();
//your append logic
$(window).scrollTop(tempScrollTop+9);
You would notice that I added '9' to the scroll position. It suits your requirement in the given fiddle. But when you implement this on your actual site, you would have to calculate the height of new appended divs dynamically and add that height instead of '9'.

To keep an element where it is in the window after something changes above it, try this:
var tmp = $('#element').offset().top - $(document).scrollTop();
// add stuff
$(document).scrollTop($('#element').offset().top - tmp);

Scroll page to a certain point then start scrolling a div's overflow content using only one scrollbar

I'm after some information on how to make the page's scroll bar scroll the overflow content of a div instead of the page once its scrolled to a certain point.
The end outcome is to scroll the page to the extent that the header isn't visible anymore, but from that point forward scroll the contents of the div - with the main scrollbar, not two nested scrollbars.
If the user scrolls back up, so that the div contents are all the way at the top again, the page should resume scroll and show the header again.

You can do it using the scrollTop property of your elements. First you'd need to determine where your header ended (the point to scroll your window to):
var header = $('#header');
var headerBottom = header.offset().top + header.height();
Then you could animate your window's scrollbar to this position:
$(window).animate({scrollTop: headerBottom});
Once that was taken care of, you would then get a reference to whichever element you wanted to then scroll by and animate its scrollTop position (same code as snippet above that scrolls the window).
Finally you would need a scroll event handler so you could determine when it was time to change which element you were scrolling the content by:
$(window).scroll(function(){
// logic to determine which element should be scrolling
});

How to see if an element in offscreen

I have a list of divs, and everytime I want to go to the next div I press a key. I need to check if that div is offscreen, and if so, I need to move the screen to show that div either using anchors or another method.
What is my best option for doing this?
Just to clairify, offscreen in my case means something that can't be seen right now without scrolling down. So if you are on the StackOverflow Home Page at the top, the last question on the entire page is offscreen.

Best option is to scroll your page to the element by getting its y-offset, and checking window height and calculating where to scroll page and then you can animate your page to that point.
//height of your div
var scroll = 250;
//animate from actual position to 250 px lower in 200 miliseconds
$(window).animate({"scrollTop": "+="+scroll+"px"}, 200);
so this is not the complete code but it might give you the idea.
check out jquery scrollTop
hope it helps,
Sinan.