<!DOCTYPE html>
<html>
<head>
<style>
#DIV1 { height: 200px;
width: 200px;
margin: auto;
border: 1px solid black;
position: relative;
}
#DIV2 { width: 150px;
border: 1px solid black;
background-color: coral;
aspect-ratio: 1;
}
#DIV2original { position: absolute;
z-index: -1;
opacity: 0.5;
width: 150px;
border: 1px dashed grey;
background-color: lightgrey;
aspect-ratio: 1;
}
</style>
</head>
<body>
<h1>Change aspect-ratio property with JavaScript</h1>
<p>Click the "Try it" button to set new aspect-ratio property "16/9":</p>
<p><b>Note: </b>The grey DIV element indicates original aspect-ratio of DIV2 element.</p>
<button onclick="myFunction()">Try it</button>
<div id="DIV1">DIV1
<div id="DIV2original">DIV2</div>
<div id="DIV2">DIV2</div>
</div>
<script>
function myFunction() { document.getElementById("DIV2").style.aspectRatio = "16/9";}
</script>
</body>
</html>