W3Schools Tryit Editor

<!DOCTYPE html>
<html>
<head>
<style> 
#main {
  width: 350px;
  height: 350px;
  border: 1px solid #c3c3c3;
  display: flex;
  flex-direction: row;
}

#main div {
  width: 50px;
  height: 50px;
}
</style>
</head>
<body>

<h1>Change flex-direction with JavaScript</h1>

<p>Click the "Try it" button to set the value of the flexDirection property to "column-reverse".</p>

<p><b>Note:</b> Internet Explorer 10 and earlier versions earlier versions do not support the flexDirection property.</p>

</body>

</html>