вот так в FireFox работает
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title></title>
<script type="text/javascript">
function valid() {
var parentNode = document.getElementById("_handler");
for (var i = 0;i != parentNode.childNodes.length; i++) {
var node = parentNode.childNodes[i];
node.style.background = "#FFA090";
}
}
</script>
</head>
<body>
<div id="_handler"><div>Participants</div><div>Roles
<label>
<input type="radio" value="1">
</label>
</div><div>Users List
<label>
<input type="radio" value="2">
</label>
</div></div>
<input type="button" onclick="valid();" value="ok">
</body>
</html>