Source code
Revision control
Copy as Markdown
Other Tools
Test Info: Warnings
- This test has a WPT meta file that expects 1 subtest issues.
- This WPT test may be referenced by the following Test IDs:
- /html/semantics/embedded-content/the-img-element/image-base-url.html - WPT Dashboard Interop Dashboard
<!DOCTYPE html>
<html>
<head>
<title>Image load parses URL after microtask runs</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
</head>
<body>
<script>
// This test asserts two things:
// 1.) That Document base URL modifications that take place in between an
// image loading microtask being scheduled and executed are reflected in
// the final image request
// 2.) That subsequent changes to a Document's base URL before an image is
// inserted into the DOM do not lead to the image being refetched when it
// is inserted asynchronously later. This is because image insertion is
// not a relevant mutation
promise_test(async t => {
const image = new Image();
image.src = 'green.png';
// Dynamically insert a <base> tag that should influence the above image
// request because the above code triggers a microtask to continue fetching
// the image, which will run while we await `loadPromise` below.
const base = document.createElement('base');
base.setAttribute('href', 'resources/');
document.head.append(base);
const loadPromise = new Promise((resolve, reject) => {
image.addEventListener('load', e => {
resolve();
}, {once: true});
image.addEventListener('error', e => {
reject('The image must load');
}, {once: true});
});
// The image should load successfully, since its request was influenced by the
// <base> element which points the request to the right directory.
await loadPromise;
// Now manipulate the <base> element to point to a bogus directory.
base.setAttribute('href', 'bogus/');
document.body.append(image);
const timeoutPromise = new Promise(resolve => t.step_timeout(resolve, 1500));
const imageErrorPromise = new Promise((resolve, reject) => {
image.addEventListener('load', e => {
reject('The image should not be refetched upon insertion and load, ' +
'because (1) insertion is not a relevant mutation, and (2) the ' +
'new relative URL should not resolve to a real resource');
}, {once: true});
image.addEventListener('error', e => {
reject('The image should not be refetched upon insertion, because ' +
'insertion is not a relevant mutation');
}, {once: true});
});
await Promise.race([timeoutPromise, imageErrorPromise]);
}, "An image should not be refetched upon insertion asynchronously after its " +
"Document's base URL changes");
</script>
</body>
</html>