We Keep Coding

Change element's position via animation in ReactJS

I am trying to change the position of my slip element via animation transition whenever a user scrolls to the bottom of the page. The problem that I'm having is that I don't know how to switch the positioning from flex to relative. The slip element needs to be positioned above the footer.
I've managed to achieve this with only switching classes but I don't like the jerking animation so I wanted to add some transition but now I don't know how to make it stick above the footer.
How do I make the slip element stick on top of the footer and not be fixed when a user scrolls to the bottom of the page? The goal is to achieve this with a smooth transition/animation.
Here is my stackblitz example of the problem.

This isn't really a ReactJS question, it's more of a question about HTML and CSS styling.
I would get the position of the footer: footer.offsetTop, and then I could get the user's scroll position: window.scrollY and the window height: window.innerHeight. Using all of these values, I would determine if the user has scrolled to the point where the footer is visible, and if so, make the slip element have an absolute position where the bottom is set to the footer.offsetTop
That should, in theory, work.
I actually found a stack overflow question just for determining if an element is scrolled into view: How to check if element is visible after scrolling? so that should help some.

Mouse scroll direction changes function

I am trying to create a web page which has some interesting functionality.
Simplified, the page has a div which covers almost full screen (top and left edges show the background). Inside that div is a scrollable text area.
I need to implement functionality where mouse wheel down moves the almost-full-screen-div down until it goes out of sight. Then mouse scroll up moves it back up until it is in the original position after which mouse scroll up is supposed to scroll the text area down. And vice versa, crolling up from initial position scrolls the text area down. All this regardless of the cursor position.
I'm not sure how to approach this problem so any suggestions and tips appreciated.

I belive what you are asking is this;
Live Demo
Referance: Capture Scroll on Overflow:Hidden elements

overflow-x: scroll and overflow-y:visible nightmare with x-scrolling and dropdown menu

Before i start, I wanted to let you know that I have been searching high and low for a solution to my issue but the closest thread I've found is unfortunately without the answer to the actual problem - Position absolute inside div with overflow-x scroll and overflow-y visible
Essentially I got main page where I am dynamically loading some other pages and on some of them I used dropdown listboxes. It happened that I haven't noticed it earlier as content any of the pages wasn't wide enough for me to spot the problem.
The problem I face is absolutely positioned div (which contain dropdown) and visible horizontal scroll bar on the parent of this div. When I scroll my page horizontally the dropdown div stays in the same place on the screen. I read about "popping out" absolute divs under this link:https://css-tricks.com/popping-hidden-overflow/ but even there, I can observe similar issue I am currently facing, which is appearing of the vertical scroll on the parent element. I am trying to achieve similar effect like here:
http://jsfiddle.net/matcygan/4rbvewn8/7/ but stop vertical scroll bar to appear when the listbox is expanded - instead it should overflow the box and party cover horizontal scroll bar. Here I've found another prompt example how can I achieve it http://jsfiddle.net/b5fYH/ but when i try to play with it and make red boxes scrollable with content as well as overflowing outside of the content vertically, without creating vertical scrollbar, I am failing... I am also fine with using JS if CSS on it's own can't deliver such effect.
In the end after 3 days battle, the CSS won and I need to ask for a help...
Any support will be greatly appreciated.
Thanks in advance.

Attach Horizontal Scrollbar to bottom of window if scrollable div is taller than window

I have a div that is taller than the window but is contained within a certain width. This causes the div to get a horizontal scrollbar at the very bottom. The problem with this is it makes it hard for users to scroll left and right within the div.
I would like to know if it is possible to attach a scrollbar to the bottom of the screen until the user scrolls down to the bottom of the div.
To give you an idea of what I would like to accomplish. Codrops created a nice table that once you scroll past the table header it attaches its self to the top of the screen. Here is the demo of that http://tympanus.net/Tutorials/StickyTableHeaders/. I want to do this but with a scrollbar attaching to the bottom of the screen. I am sorry I can't provide things I have tried, because I don't even know where to start when trying to accomplish this.

You can create empty container with the same width as your div and set it to fixed position. Then sync scrolling position of these 2 DIVs using jQuery. Example on jsFiddle.
jQuery(function($){
$('.content').on('scroll', function(){
$('.scroller').scrollLeft($(this).scrollLeft());
});
$('.scroller').on('scroll', function(){
$('.content').scrollLeft($(this).scrollLeft());
});
});
Hiding/showing external scrollbar depending on page scroll offset is left for you as homework :)

How to prevent div from scrolling out of page

I have a div whose height is 500px. When I scroll the page down, I would like the div to move as the page scrolls, but I would like it to stop scrolling with the page after the 250px of the div are out of the view. The rest of the page should keep scrolling but the div should act as fixed after it is 250px visible on the page.
Additionally, when I scroll up, I would like the div to remain at 250px invisible until the user has scrolled all the way to the top (with the final 250px remaining) in which case the div should suddenly become a part of the page again and scroll with it.
I am assuming that this can be done only with JavaScript, but how?

OK, using the keywords suggested by Mike Brant up in the comments, my Google search produced some good results. It appears that the functionality I was after is called sticky div, or sticky menu, sticky footer, or likewise.
By looking at the code of those javascripts I was able to understand the concept behind it. Now, it's time to play with it and adjust to my particular needs.