layout-instability
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WICG
A proposal for a Layout Instability specification
The non-normative definitions of DCLS and CLS did not include any mention of the recent user input exclusion, even though it was used in the sample calculation code. Fixes: #113...
The spec mentions that: > The cumulative layout shift (CLS) score is the sum of every layout shift value that is reported inside a top-level browsing context, **plus a fraction...
Hello team, When trying to create a PerformanceObserver to log layout-shift entries to the console, as is : export async function checkCLS2(page, maxLCP=ConstUtils.maxLCP) { const CLS = await page.evaluate(() =>...
[Margin collapsing](https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Box_Model/Mastering_margin_collapsing) can sometimes turn a small shift on a child element into a large shift on a parent/sibling element. For example: * Visit this demo https://cls-iframe-problem.glitch.me/iframe.html * Using console,...
Context: a webpage which uses cross-frame communication (e.g. postMessage) to make changes to an another iframe in direct response to interactions. Visually, this looks exactly as if the shift happened...
https://wicg.github.io/layout-instability/#report-the-layout-shift says > Set newEntry’s [name](https://w3c.github.io/performance-timeline/#dom-performanceentry-name) attribute to "layout-shift". However, Chromiums return an empty string and this test also asserts `""`: https://github.com/web-platform-tests/wpt/blob/0c1b9d1622/layout-instability/buffer-layout-shift.html#L25
While crawling [Layout Instability API](https://wicg.github.io/layout-instability/), the following links to other specifications were detected as pointing to non-existing anchors, which should be fixed: * [ ] https://w3c.github.io/resource-timing/#sec-privacy-security * [ ] https://www.w3.org/TR/css-values-4/#pixel-unit...
The spec should make it clearer whether `transform` affects "visual representation" and layout shift
The explainer and spec don't seem to agree on what the impact of CSS `transform` is, with respect to layout shift. The spec: (1) doesn't mention the word transform at...
Ambiguous language in section 2.2 here: https://wicg.github.io/layout-instability/#sec-basic-concepts > there does not exist an Element P such that > [...conditions...] and: > 4. N has not shifted in the coordinate space...
The Usage Example does showcase ignoring recent input and does include a comment: ` // Only count layout shifts without recent user input.`, but I do not see this explicitly...