W3Schools Tryit Editor

<!DOCTYPE html>
<html>
<head>
<style>
#container {
  width: 80%;
  aspect-ratio: 2/1;
  margin: auto;
  border: solid black 2px;
  overflow-x: hidden;
  overflow-y: scroll;
  scroll-snap-type: y mandatory;
  scroll-padding-block-start: 0;
}

.blue {
  background-color: lightblue;
  width: 80%;
  aspect-ratio: 5/2;
}

.green {
  background-color: lightgreen;
  width: 60%;
  aspect-ratio: 2/1;
}

.blue, .green {
  margin: 2px;
  scroll-snap-align: start;
}
</style>
</head>
<body>

<h1>Change scroll-padding-block-start property with JavaScript</h1>

<p>Try first to scroll to see how the child elements snap into place on start of container in block direction.</p>

<p>Now, click button, click inside the container, and see how scrolling behaviour has changed. The elements still snap on start of container like before, but now with a 20px distance in block direction from the start of the container to the child elements.</p>

</body>
</html>

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<!DOCTYPE html><html><head><style>#container {  width: 80%;  aspect-ratio: 2/1;  margin: auto;  border: solid black 2px;  overflow-x: hidden;  overflow-y: scroll;  scroll-snap-type: y mandatory;  scroll-padding-block-start: 0;}​.blue {  background-color: lightblue;  width: 80%;  aspect-ratio: 5/2;}​.green {  background-color: lightgreen;  width: 60%;  aspect-ratio: 2/1;}​.blue, .green {  margin: 2px;  scroll-snap-align: start;}</style></head><body>​<h1>Change scroll-padding-block-start property with JavaScript</h1>​<p>Try first to scroll to see how the child elements snap into place on start of container in block direction.</p>​<p>Now, click button, click inside the container, and see how scrolling behaviour has changed. The elements still snap on start of container like before, but now with a 20px distance in block direction from the start of the container to the child elements.</p>​<button onclick="myFunction()">Try it</button>​<div id="container">  <div class="blue"></div>  <div class="green"></div>  <div class="blue"></div>