| <!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> |
| <script> |
| let beforeRender; |
| let img; |
| // Number of characters to be read on the initial read, before sleeping. |
| // Should be sufficient to do at least a first scan. |
| let numInitial = 75; |
| let sleep = 500; |
| async_test(function(t) { |
| if (!window.PerformanceElementTiming) { |
| assert_unreached("PerformanceElementTiming is not implemented"); |
| } |
| const img_src = 'resources/progressive-image.py?name=square20.jpg&numInitial=' |
| + numInitial + '&sleep=' + sleep; |
| const observer = new PerformanceObserver( |
| t.step_func_done(function(entryList) { |
| assert_equals(entryList.getEntries().length, 1); |
| const entry = entryList.getEntries()[0]; |
| const index = window.location.href.lastIndexOf('/'); |
| const pathname = window.location.href.substring(0, index) + '/' + |
| img_src; |
| // Since the image is only fully loaded after the sleep, the render timestamp |
| // must be greater than |beforeRender| + |sleep|. |
| checkElement(entry, pathname, 'my_image', '', beforeRender + sleep, img); |
| checkNaturalSize(entry, 20, 20); |
| }) |
| ); |
| observer.observe({entryTypes: ['element']}); |
| |
| img = document.createElement('img'); |
| img.src = img_src; |
| img.setAttribute('elementtiming', 'my_image'); |
| document.body.appendChild(img); |
| beforeRender = performance.now(); |
| t.step_timeout(() => {assert_true(0);}, 2000); |
| }, "Element Timing: image render timestamp occurs after it is fully loaded."); |
| </script> |