test.xhtml

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="fr">
<head>
    <title>XHTML</title>
</head>
<body>

<p>Bla bla bla</p>

<style>
<!-- xml comment -->
parentRule {
  /* oups, xml error, but nesteed rule :/ */
  & childRule {
  }
}

/* <![CDATA[ */
<!-- oups -->
parentRule {
  & childRule {
  }
}
/* ]]> */

<![CDATA[
<!-- oups -->
parentRule {
  & childRule {
  }
}
]]>
</style>

<script>
<!-- xml comment -->
console.log(a & b);
/* <![CDATA[ */
<!-- oups -->
console.log(a & b);
/* ]]> */

<![CDATA[
<!-- oups -->
console.log(a & b);
]]>
</script>

</body>
</html>