<script>
try {
  top.navigator;
  console.log('FAIL');
} catch (e) {
  console.log("iframe1: " + e.toString());
}
this.x = 7;
window.name = 'navigator';
try {
  top.navigator;
  console.log('FAIL');
} catch (e) {
  console.log("iframe1: " + e.toString());
}
</script>

<script>
try {
  top.navigator;
  console.log('FAIL');
} catch (e) {
  console.log("iframe2: " + e.toString());
}
</script>