javascript reverse () can reverse the order of elements in the array, which will change the original array, without creating a new array
<!DOCTYPE html>
<html>
<head>
<title>Runde</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<script type="text/javascript">
var arr = new Array(3)
arr [0] = "John Doe"
arr [1] = "John Doe"
arr [2] = "Wang Wu"
document.write(arr+"<br />")
document.write(arr.reverse())
</script>
</head>
<body>
</body>
</html>