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Test Info:
- This WPT test may be referenced by the following Test IDs:
- /preload/preconnect-onerror-event.html - WPT Dashboard Interop Dashboard
<!DOCTYPE html>
<html>
<title>Makes sure that preconnected resources do not trigger load or error events</title>
<meta name="timeout" content="long">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/common/get-host-info.sub.js"></script>
<body>
<script>
const {HTTP_REMOTE_ORIGIN} = get_host_info();
/**
* Test workflow:
* - Create preconnect link
* - Wait 200 ms
* - Create preload link
* Event listeners for 'load' and 'error' are attached to both links.
* The first event listener that fires is tested to see which element fired it.
* The event should always be fired by the preload element because per spec, the preconnect link should never fire these events:
*
* This test assumes that the preload link element fires 'load' and 'error' events correctly, otherwise the test will timeout.
*/
function test_preconnect(origin, resource, desc) {
promise_test(async t => {
const result = await new Promise(async didLoad => {
const href = `${origin}${resource}`;
for (const rel of ['preconnect', 'preload']) {
const link = document.createElement('link');
link.href = href;
link.as = 'script';
link.rel = rel;
link.addEventListener('load', () => didLoad({rel, type: 'load'}));
link.addEventListener('error', () => didLoad({rel, type: 'error'}));
document.head.appendChild(link);
await new Promise(resolve => t.step_timeout(resolve, 200));
}
});
assert_equals(result.rel, 'preload');
}, desc);
}
test_preconnect(HTTP_REMOTE_ORIGIN, '/preload/resources/dummy.js', 'Preconnect should not fire load (or error) events');
test_preconnect('http://NON-EXISTENT.origin', '/preload/resources/dummy.js', 'Preconnect should not fire error (or load) events for non-existent origins');
test_preconnect('some-scheme://URL', '/preload/resources/dummy.js', 'Preconnect should not fire error (or load) events for non-http(s) scheme');
</script>
</body>
</html>