EN VI

Javascript - How to make images appear when scrolling properly?

I'm trying to make two images appear in a "front-image" section when I scroll. When the user scrolls down, the images should behave as follows:

top-image: must go down
bottom-image: must go up

when the user scrolls up the behavior must be reversed.

What I've tried so far using a pinch of js to follow the scroll:

  const frontImageSection = document.querySelector('.front-image');
  const topImage = document.querySelector('.top-image');
  const bottomImage = document.querySelector('.bottom-image');

  window.addEventListener('scroll', () => {
    const scrollPosition = window.scrollY;
    const windowHeight = window.innerHeight;
    const frontImageSectionTop = frontImageSection.offsetTop;
    const frontImageSectionHeight = frontImageSection.offsetHeight;

    const topImageOffset = (scrollPosition / frontImageSectionHeight) * 100;

    let bottomImageOffset = -((scrollPosition / frontImageSectionHeight) * 100);

    topImage.style.transform = `translateY(${topImageOffset}%)`;
    bottomImage.style.transform = `translateY(${bottomImageOffset}%)`;
  });

  body {
    height: 300vh;
  }

  .front-image {
    top: 20%;
    position: relative;
    padding-top: 96.2px;
    overflow: hidden;
  }

  .front-image .top-image,
  .front-image .bottom-image {
    position: fixed;
    transition: transform 0.3s ease-in-out;
    width: 200px;
  }

  .front-image .top-image {
    top: 0;
    right: 10%;
  }

  .front-image .bottom-image {
    bottom: 0;
    left: 10%;
  }

  .front-image .content picture img {
    width: 100%;
    height: 525px;
    object-fit: cover;
  }

<body>
  <section class="front-image">
    <div class="square-box"></div>
    <div class="container-fluid">
      <div class="row">
        <div class="col-md-12 px-0">
          <div class="content">
            <picture>
              <img src="https://i.imgur.com/bTX82bl.jpeg" class="">
            </picture>
          </div>
        </div>
      </div>
    </div>
    <img src="https://i.ibb.co/Vvy6Cfp/Pngtree-isolated-cat-on-white-background-9158356.png" alt="Logo"
      class="top-image">
    <img src="https://i.ibb.co/Vvy6Cfp/Pngtree-isolated-cat-on-white-background-9158356.png" alt="Logo"
      class="bottom-image">
  </section>
</body>

but the behavior is quite bizarre and doesn't even seem smooth, also, the images should appear within the section, but for some reason they pop out I can't figure out where I'm going wrong, could anyone help me?

Thanks in advance

Solution:

You can check this. Now cats don't show when scrollposition is 0

const frontImageSection = document.querySelector('.front-image');
const topImage = document.querySelector('.top-image');
const bottomImage = document.querySelector('.bottom-image');

window.addEventListener('scroll', () => {


  const scrollPosition = window.scrollY;
  if(scrollPosition==0){
    topImage.style.opacity = 0;
    bottomImage.style.opacity = 0;
  }else{
    topImage.style.opacity = 1;
    bottomImage.style.opacity = 1;
  }
  const windowHeight = window.innerHeight;
  const frontImageSectionTop = frontImageSection.offsetTop;
  const frontImageSectionHeight = frontImageSection.offsetHeight;

  const topImageOffset = (scrollPosition / frontImageSectionHeight) * 100;

  let bottomImageOffset = -((scrollPosition / frontImageSectionHeight) * 100);

  topImage.style.transform = `translateY(${topImageOffset}%)`;
  bottomImage.style.transform = `translateY(${bottomImageOffset}%)`;
});

body {
    height: 300vh;
  }

  .front-image {
    top: 20%;
    position: relative;
    /* padding-top: 96.2px; */
    overflow: hidden;
    scroll-behavior: smooth; /* added smooth scroll*/
  }

  .front-image .top-image,
  .front-image .bottom-image{
    opacity: 0;
    position: absolute; /* changed position to absolute*/
    transition: all 0.3s linear; /*changed transition to linear*/
    width: 200px;
    scroll-behavior: smooth; /* added smooth scroll*/
  }

  .front-image .top-image {
    padding: 0;
    top: 0;
    right: 10%;
  }

  .front-image .bottom-image {
    padding: 0;
    bottom: 0;
    left: 10%;
  }

  .front-image .content picture img {
    width: 100%;
    height: 525px;
    object-fit: cover;
  }

    <section class="front-image">
        <div class="square-box"></div>
        <div class="container-fluid">
          <div class="row">
            <div class="col-md-12 px-0">
              <div class="content">
                <picture>
                  <img src="https://i.imgur.com/bTX82bl.jpeg" class="">
                </picture>
              </div>
            </div>
          </div>
        </div>
        <img src="https://i.ibb.co/Vvy6Cfp/Pngtree-isolated-cat-on-white-background-9158356.png" alt="Logo"
          class="top-image">
        <img src="https://i.ibb.co/Vvy6Cfp/Pngtree-isolated-cat-on-white-background-9158356.png" alt="Logo"
          class="bottom-image">
      </section>