<script>
if (window.testRunner)
    testRunner.dumpAsText();

window[0] = {
    a: "1",
    f: function() {
        alert("FAIL: Child called parent.f()");
    }
};
</script>
<iframe src="data:text/html,<script>try { alert(parent[0].a); } catch (e) { alert('PASS: Access to parent[0].a threw exception.'); }</script><script>try { parent[0].f(); } catch (e) { alert('PASS: Access to parent[0].f() threw exception.'); }</script>"></iframe><br>
This test passes if the access is forbidden.