| <!DOCTYPE html> |
| <html> |
| <meta charset=utf-8 /> |
| <title>Element Timing: buffer elements before onload</title> |
| <script src=/resources/testharness.js></script> |
| <script src=/resources/testharnessreport.js></script> |
| <script src="resources/element-timing-helpers.js"></script> |
| <body> |
| <img src=resources/slow-image.py?name=square20.png&sleep=500> |
| <script> |
| /* |
| In this test, a slow image is added to the frame to delay onload. The entry |
| is available from the observer with the buffered flag set to true. |
| */ |
| async_test(function(t) { |
| assert_implements(window.PerformanceElementTiming, "PerformanceElementTiming is not implemented"); |
| beforeRender = performance.now(); |
| const img = document.createElement('img'); |
| img.src = 'resources/square20.jpg'; |
| img.setAttribute('elementtiming', 'my_image'); |
| img.setAttribute('id', 'my_id'); |
| document.body.appendChild(img); |
| |
| // this PerformanceObserver should be notified about the previously |
| // buffered element entry |
| new PerformanceObserver(t.step_func((entryList, observer) => { |
| assert_equals(entryList.getEntries().length, 1); |
| entryList.getEntries().forEach(entry => { |
| assert_equals(entry.entryType, "element"); |
| const pathname = window.location.origin + '/element-timing/resources/square20.jpg'; |
| checkElement(entry, pathname, 'my_image', 'my_id', beforeRender, img); |
| checkNaturalSize(entry, 20, 20); |
| observer.disconnect(); |
| t.done(); |
| }); |
| })).observe({ |
| type: "element", |
| buffered: true |
| }); |
| }, "Element Timing: image loads before onload available from buffered flag."); |
| |
| </script> |
| </body> |
| </html> |