| <!DOCTYPE HTML> |
| <meta charset=utf-8> |
| <title>Element Timing: observe elements with the same resource</title> |
| <body> |
| <style> |
| body { |
| margin: 0; |
| } |
| </style> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <script src="resources/element-timing-helpers.js"></script> |
| <script> |
| let beforeRender; |
| let numEntries = 0; |
| let loadTime1; |
| let loadTime2; |
| let renderTime1; |
| let renderTime2; |
| let img; |
| let img2; |
| async_test(function (t) { |
| assert_implements(window.PerformanceElementTiming, "PerformanceElementTiming is not implemented"); |
| const observer = new PerformanceObserver( |
| t.step_func(function(entryList) { |
| assert_equals(entryList.getEntries().length, 1); |
| const entry = entryList.getEntries()[0]; |
| const pathname = window.location.origin + '/element-timing/resources/square100.png'; |
| // Easier to check the |element| attribute here since element ID is the same for both images. |
| checkElement(entry, pathname, entry.identifier, 'image_id', beforeRender, null); |
| checkNaturalSize(entry, 100, 100); |
| if (entry.identifier === 'my_image') { |
| ++numEntries; |
| loadTime1 = entry.loadTime; |
| renderTime1 = entry.renderTime; |
| assert_equals(entry.element, img); |
| |
| img2 = document.createElement('img'); |
| img2.src = 'resources/square100.png'; |
| img2.setAttribute('elementtiming', 'my_image2'); |
| img2.setAttribute('id', 'image_id'); |
| document.body.appendChild(img2); |
| beforeRender = performance.now(); |
| } |
| else if (entry.identifier === 'my_image2') { |
| ++numEntries; |
| loadTime2 = entry.loadTime; |
| renderTime2 = entry.renderTime; |
| assert_equals(entry.element, img2); |
| } |
| if (numEntries == 2) { |
| assert_greater_than(loadTime2, loadTime1, 'Second image loads after first.'); |
| assert_greater_than(renderTime2, renderTime1, 'Second image renders after first'); |
| t.done(); |
| } |
| }) |
| ); |
| observer.observe({entryTypes: ['element']}); |
| // We add the images 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 and height equal to 100. |
| img = document.createElement('img'); |
| img.src = 'resources/square100.png'; |
| img.setAttribute('elementtiming', 'my_image'); |
| img.setAttribute('id', 'image_id'); |
| document.body.appendChild(img); |
| beforeRender = performance.now(); |
| }; |
| }, 'Elements with elementtiming and same src are observable.'); |
| </script> |
| |
| </body> |