<!doctype html> <title>onmessage implied start()</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(); channel.port1.postMessage(1); channel.port2.onmessage = function() { setTimeout(t.step_func(function() { t.done(); }), 50); channel.port2.onmessage = t.step_func(function() { assert_unreached(); }); }; // implies start() }); </script>