<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
</head>
<body>
<div id="11">
1111
</div>
<div id="22">
2222
</div>
<script>
function insertAfter(new_item, item) {
item.parentNode.insertBefore(new_item, item.nextSibling);
}
var n = document.createElement('h1');
n.innerText = '吼吼吼';
var i = document.getElementById('11');
insertAfter(n, i);
</script>
</body>
</html>