40 lines
1.6 KiB
HTML
40 lines
1.6 KiB
HTML
<!DOCTYPE html>
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<html>
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<meta charset=utf-8 />
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<title>Element Timing: buffer elements before onload</title>
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<script src=/resources/testharness.js></script>
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<script src=/resources/testharnessreport.js></script>
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<script src="resources/element-timing-helpers.js"></script>
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<body>
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<script>
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let beforeRender;
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let img;
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// Number of characters to be read on the initial read, before sleeping.
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// Should be sufficient to do at least a first scan.
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let numInitial = 75;
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let sleep = 500;
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async_test(function(t) {
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assert_implements(window.PerformanceElementTiming, "PerformanceElementTiming is not implemented");
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const img_src = 'resources/progressive-image.py?name=square20.jpg&numInitial='
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+ numInitial + '&sleep=' + sleep;
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const observer = new PerformanceObserver(
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t.step_func_done(function(entryList) {
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assert_equals(entryList.getEntries().length, 1);
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const entry = entryList.getEntries()[0];
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const pathname = window.location.origin + '/element-timing/' + img_src;
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// Since the image is only fully loaded after the sleep, the render timestamp
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// must be greater than |beforeRender| + |sleep|.
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checkElement(entry, pathname, 'my_image', '', beforeRender + sleep, img);
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checkNaturalSize(entry, 20, 20);
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})
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);
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observer.observe({entryTypes: ['element']});
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img = document.createElement('img');
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img.src = img_src;
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img.setAttribute('elementtiming', 'my_image');
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document.body.appendChild(img);
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beforeRender = performance.now();
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t.step_timeout(() => {assert_true(0);}, 2000);
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}, "Element Timing: image render timestamp occurs after it is fully loaded.");
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</script>
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