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HTML

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HTML

              
                <div class="grid"><div class="cell"><div class="cell-wrap">
  <h3>No CLS Solution</h3>
  <p>Praesent lacus est, finibus eget ipsum ac, tincidunt sollicitudin velit. Proin rutrum maximus commodo. Cras interdum dictum nisi vel dapibus.</p>
<img alt="surfers" />
<p>Cras vel finibus nunc. Nam purus mauris, ultricies eget hendrerit eu, placerat at elit. Suspendisse tortor ex, euismod quis efficitur fringilla, interdum sed libero. Maecenas nec erat id augue dignissim bibendum. Nunc mollis ligula ut enim mattis ultrices porta quis quam. Nam in feugiat tellus, at ullamcorper neque. Vestibulum eget lorem dapibus, lobortis libero eget, lobortis odio.</p><p><a href="#">This link will jump because of CLS</a></p></div></div>
<div class="cell"><div class="cell-wrap">
  <h3>With CLS Solution</h3>
  <p>Praesent lacus est, finibus eget ipsum ac, tincidunt sollicitudin velit. Proin rutrum maximus commodo. Cras interdum dictum nisi vel dapibus.</p>
<img alt="surfers" class="cls"/>
<p>Cras vel finibus nunc. Nam purus mauris, ultricies eget hendrerit eu, placerat at elit. Suspendisse tortor ex, euismod quis efficitur fringilla, interdum sed libero. Maecenas nec erat id augue dignissim bibendum. Nunc mollis ligula ut enim mattis ultrices porta quis quam. Nam in feugiat tellus, at ullamcorper neque. Vestibulum eget lorem dapibus, lobortis libero eget, lobortis odio.</p><p><a href="#">This link will stay right here, no CLS</a></p></div></div>
</div>
              
            
!

CSS

              
                body {
  background: #ccc;
}
img {
  border: solid #ccc 1px;
  width: 300px;
  display: block;
}
.cell-wrap {
  background: #fff;
  padding: 1rem;
}
.cell-wrap > *:first-child {
  margin-top: 0;
}
.cell-wrap > *:last-child {
  margin-bottom: 0;
}
.grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
}
.cls {
  aspect-ratio: 640/480;
}
              
            
!

JS

              
                const img_src = 'https://i.imgur.com/v2nFDU0l.jpg';
const images = document.querySelectorAll('img');
setInterval(() => {
  Array.from(images).forEach(image => {
     image.src = image.src === img_src ? '' : img_src;
  });
}, 2000)
              
            
!
999px

Console