JavaScript for循环倒序遍历数组的实现方法

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>倒序输出数组元素</title>
</head>
<body>
<script type="text/javascript">
var a=[1,2,3,4]
for(var i=a.length-1;i>=0;i--){
document.write(a[i]+'<br>');}
</script>
hellp
</body>
</html>