<html>
<body>
The top navigation from this iframe should be blocked. This text should appear.
<script>
window.onload = function()
{
    try {
        top.location = "navigation-changed-iframe.html";
        top.postMessage("FAIL", "*");
    } catch(e) {
        top.postMessage("PASS", "*");
    }
}
</script>
</body>
</html>