| <!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) { |
| if (!window.PerformanceElementTiming) { |
| assert_unreached("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> |