Regex for div and it content

C#

string html = @"<div class=""ddd"">ddd</div>

<div class=""s"">hello<div>world</div>
</div>
<div class=""ddd"">ddd</div>";

MessageBox.Show(Regex.Replace(html, @"<div class=""s""[^>]*>((?:(?:(?!<div[^>]*>|</div>).)+|<div[^>]*>([\s\S]*?)</div>)*)</div>", "XXXXXX", RegexOptions.IgnoreCase | RegexOptions.Singleline));

PHP

<?php
$cnt = '<div class="ddd">hello</div>

<div class="s">hello<div>world</div>
</div>
<div class="ddd">hello</div>';

$cnt = preg_replace('#<div\s+class="s"[^>]*>((?:(?:(?!<div[^>]*>|</div>).)+|<div[^>]*>[\s\S]*?</div>)*)</div>#six', '<h1>MAC WAS HERE</h1>', $cnt);

echo $cnt;

JavaScript

<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
<script type="text/javascript">
    function hello() {
        var cnt = document.body.innerHTML+'';
        cnt = cnt.replace(new RegExp('[\r\n]', 'gi'), '');
        cnt = cnt.replace(new RegExp('<div class="s">((?:(?:(?!<div[^>]*>|</div>).)+|<div[^>]*>.*?</div>)*)</div>', 'i'), '<h1>XXXX</h1>');
        document.body.innerHTML = cnt;
    }
</script>
</head>
<body onload="hello()">
    <div class="ddd">hello</div>

    <div class="s">hello<div>world</div>
    </div>
    <div class="ddd">hello</div>
</body>
</html>