mirror of
https://github.com/LadybirdBrowser/ladybird
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ded42e649b
We were mimicking Firefox' behavior that whenever a programmatic change to an <input>'s or <textarea>'s selection happened, the new selection focus is brought into view by scrolling. Currently we run a layout update synchronously for that to make sure we have the fragment's correct dimensions, which caused a significant performance regression in Speedometer. Since this is non-standard behavior, let's mimic Chromium instead which does not scroll at all - only for direct user initiated input such as typing. Relevant issues: * https://github.com/whatwg/html/issues/6217 * https://bugzilla.mozilla.org/show_bug.cgi?id=232405 * https://issues.chromium.org/issues/41081857
38 lines
1.1 KiB
HTML
38 lines
1.1 KiB
HTML
<!DOCTYPE html>
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<style>
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.row {
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display: flex;
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align-items: center;
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padding: 4px;
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}
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</style>
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<input id="inp" />
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<div id="app"></div>
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<script src="include.js"></script>
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<script>
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test(() => {
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const input = document.querySelector("#inp");
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const app = document.querySelector("#app");
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for (let i = 0; i < 2000; i++) {
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const row = document.createElement("div");
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row.className = "row";
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row.innerHTML = `<input type="checkbox"><span>${i}</span><button>x</button>`;
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app.appendChild(row);
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}
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input.focus();
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input.offsetWidth;
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// Performance test: setting input.value must not synchronously trigger a full layout.
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const values = ["a", "ab"];
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const start = performance.now();
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for (let i = 0; i < 2000; i++) {
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app.children[i % 2000].style.padding = (4 + (i % 2)) + "px";
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input.value = values[i % 2];
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}
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const elapsed = performance.now() - start;
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println(elapsed < 5000 ? "PASS" : `FAIL: took ${elapsed.toFixed(0)}ms`);
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});
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</script>
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