1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
|
<!DOCTYPE HTML>
<meta charset=utf-8>
<title>Element Timing: do not observe a disconnected image</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
async_test(function (t) {
assert_implements(window.PerformanceElementTiming, "PerformanceElementTiming is not implemented");
const observer = new PerformanceObserver(
t.step_func_done(() => {
// The image should not have caused an entry, so fail test.
assert_unreached('Should not have received an entry!');
})
);
observer.observe({entryTypes: ['element']});
// We add the image during onload to be sure that the observer is registered
// in time for it to observe the element timing.
window.onload = () => {
// Add image of width equal to 100 and height equal to 100.
const img = document.createElement('img');
img.src = 'resources/square100.png';
img.setAttribute('elementtiming', 'my_image');
img.setAttribute('id', 'my_id');
// Image has been created but not added.
// Wait for 500ms and end test, ensuring no entry was created.
t.step_timeout(() => {
t.done();
}, 500);
};
}, 'Image which is not added to DOM tree is not observable.');
</script>
|
