messageerror.html - mozsearch

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This WPT test may be referenced by the following Test IDs:
- /webmessaging/messageerror.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<title>onmessageerror content attribute</title>

<link rel="author" title="Domenic Denicola" href="mailto:d@domenic.me">

<link rel="help" href="https://html.spec.whatwg.org/multipage/#handler-onmessageerror">

<script src="/resources/testharness.js"></script>

<script src="/resources/testharnessreport.js"></script>

<body>

<script>

"use strict";

window.messageErrorHappened = false;

function cleanup() {

  window.messageErrorHappened = false;

  document.body.removeAttribute("onmessageerror");

test(() => {

  assert_equals(document.body.onmessageerror, null, "body");

  assert_equals(window.onmessageerror, null, "window");

}, "The default value of onmessageerror is null");

test(t => {

  t.add_cleanup(cleanup);

  document.body.setAttribute("onmessageerror", "window.messageErrorHappened = true;")

  const compiledHandler = document.body.onmessageerror;

  assert_equals(typeof compiledHandler, "function", "The onmessageerror property must be a function");

  compiledHandler();

  assert_true(window.messageErrorHappened, "Calling the handler must run the code");

}, "The onmessageerror content attribute must be compiled into the onmessageerror property");

test(t => {

  t.add_cleanup(cleanup);

  document.body.setAttribute("onmessageerror", "window.messageErrorHappened = true;")

  window.dispatchEvent(new Event("messageerror"));

  assert_true(window.messageErrorHappened, "Dispatching the event must run the code");

}, "The onmessageerror content attribute must execute when an event is dispatched on the window");

</script>