<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<script>

function boom()
{
  document.getElementById("div1").appendChild(document.getElementById("div2"));
}

</script>

<style type="text/css">

#s1, #s2 { 
  font: 8pt arial;
}

#div1 #s1, #div1 #s2 {
  font-size: 20pt;
}

</style>
</head>

<body onload="boom();">

<div id="div1"></div>
<div id="div2"><span id="s1"><span id="s2">foo</span></span></div>

</body>
</html>