<!DOCTYPE html>
<html>
<head>
<style>
@namespace url(test);
div {
background-color: green;
}
div[dir=RTL ] 
{background-color: red !important;
}
</style>
<script>
function f() {
var elem = document.createElementNS("test","div");
elem.setAttribute("dir","rtl");
elem.appendChild(document.createTextNode("text"));
document.getElementsByTagName("body")[0].appendChild(elem); }
</script>
</head>
<body onload="f();">
</body>
</html>