<!DOCTYPE html>
<html>
<head>
  <title>window-onerror</title>
  <style>
    #result {
      width: 100px;
      height:100px;
      background-color:#0047AB;
    }
  </style>
</head>
<body>

<div id="result"></div>

<script>

function expect(condition, message) {
  if (!condition) {
    document.querySelector('#result').style.display = 'none';
    const fullMessage = `failed expectation at:
${new Error().stack}
${typeof message === 'undefined' ? '' : 'with message: ' + message}`;
    console.error(fullMessage);
  }
}

let windowOnErrorWasCalled = false;

// No need to set this to null, but there was a regression at one point where
// doing so would result in an erroneous JS error, so add this line in to get
// some extra test coverage.
window.onerror = null;

window.onerror = (message, filename, lineno, colno, error) => {
  // We allow anything that ends with "myCoolMessage" to pass, Chrome/Firefox behavior differs here
  // (Chrome: "Uncaught Error: myCoolMessage", Firefox: "Error: myCoolMessage").
  expect(/.*myCoolMessage/.test(message), message);
  // Allow any filename that ends with "window-onerror.html", in order to not couple too heavily to
  // the implementation of layout_tests.
  expect(/.*window-onerror.html/.test(filename), filename);
  expect(lineno === 89, lineno);
  // The value of the column number is not standard across major browsers.
  //   Chrome: 1 without devtools open, 7 with devtools open.
  //   Edge: Always 1.
  //   Firefox: Always 7.
  //   Safari: 18.
  expect(colno === 1 || colno === 7 || colno === 18, colno);
  expect(typeof error === 'object', typeof error);
  expect(String(error) === 'Error: myCoolMessage', String(error));

  windowOnErrorWasCalled = true;
};

// Make sure that when an event handler is added for the 'error' event via
// addEventListener, it assumes the usual function signature of just the event
// object.
let windowErrorEventHandlerCalled = false;
window.addEventListener('error', (errorEvent) => {
  expect(errorEvent.type == 'error', errorEvent.type);

  // Check the same parameters as above in the onerror attribute event handler,
  // just make sure they are passed through as an event object instead of
  // expanded.
  expect(/.*myCoolMessage/.test(errorEvent.message), errorEvent.message);
  expect(/.*window-onerror.html/.test(errorEvent.filename),
         errorEvent.filename);
  expect(errorEvent.lineno === 89, errorEvent.lineno);
  expect(errorEvent.colno === 1 || errorEvent.colno === 7 ||
         errorEvent.colno === 18, errorEvent.colno);
  expect(typeof errorEvent.error === 'object', typeof errorEvent.error);
  expect(String(errorEvent.error) === 'Error: myCoolMessage',
         String(errorEvent.error));

  windowErrorEventHandlerCalled = true;
});

if (window.testRunner) {
  window.testRunner.waitUntilDone();
}
setTimeout(() => {
  expect(windowOnErrorWasCalled);
  expect(windowErrorEventHandlerCalled);
  if (window.testRunner) {
    window.testRunner.notifyDone();
  }
}, 1);
throw new Error('myCoolMessage');

</script>

</body>
</html>