<!DOCTYPE html>
<title> postMessage(): target port and source port </title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<div id=log></div>
<script>
async_test(function(t) {
  var channel = new MessageChannel();
  var source = channel.port1;
  var target = channel.port2;
  target.start();
  target.addEventListener("message", t.step_func_done(function(e) {
    assert_equals(e.target, target);
    assert_not_equals(e.target, source);
  }), true);
  source.postMessage("ping");
});
</script>