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61 lines
2.3 KiB
HTML
61 lines
2.3 KiB
HTML
<!DOCTYPE HTML>
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<meta charset=utf-8>
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<title>Layout Instability: observe after user input</title>
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<body>
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<style>
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#myDiv { position: relative; width: 300px; height: 100px; }
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/* Disable the button's focus ring, which otherwise expands its visual rect by
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* 1px on all sides, triggering a layout shift event.
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*/
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#button { outline: none; }
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</style>
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<div id='myDiv'></div>
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<button id='button'>Generate a 'click' event</button>
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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/testdriver.js></script>
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<script src=/resources/testdriver-vendor.js></script>
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<script src=resources/util.js></script>
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<script src=/event-timing/resources/event-timing-test-utils.js></script>
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<script>
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let timeAfterClick;
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promise_test(async t => {
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assert_implements(window.LayoutShift, 'Layout Instability is not supported.');
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// Wait for the initial render to complete.
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await waitForAnimationFrames(2);
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const startTime = performance.now();
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return new Promise(resolve => {
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const observer = new PerformanceObserver(
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t.step_func(entryList => {
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const endTime = performance.now();
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assert_equals(entryList.getEntries().length, 1);
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const entry = entryList.getEntries()[0];
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assert_equals(entry.entryType, "layout-shift");
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assert_equals(entry.name, "");
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assert_greater_than_equal(entry.startTime, startTime);
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assert_less_than_equal(entry.startTime, endTime);
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assert_equals(entry.duration, 0.0);
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// The layout shift value should be:
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// 300 * (100 + 60) * (60 / maxDimension) / viewport size.
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assert_equals(entry.value, computeExpectedScore(300 * (100 + 60), 60));
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// We should see that there was a click input entry.
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assert_equals(entry.hadRecentInput, true);
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assert_greater_than_equal(timeAfterClick, entry.lastInputTime);
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resolve();
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})
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);
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observer.observe({entryTypes: ['layout-shift']});
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// User input event
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clickAndBlockMain('button').then(() => {
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timeAfterClick = performance.now();
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// Modify the position of the div.
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document.getElementById('myDiv').style = "top: 60px";
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});
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});
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}, 'Layout shift right after user input is observable via PerformanceObserver.');
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</script>
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</body>
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