Intent to Implement: ElementTiming for text

[n...@chromium.org]

Contact emails n...@chromium.org, tdre...@chromium.org Explainer https://docs.google.com/document/d/1xhPJnXf0Nqsi8cBFrlzBuHavirOVZBd8TqdD_OyrDGw/edit?usp=sharing Design docs/spec Specification: https://wicg.github.io/element-timing/ Note that we have not added text to the spec but this is where it will be added.

TAG review https://github.com/w3ctag/design-reviews/issues/326 I'm hoping that they will agree to add text to the review of image Element Timing (just asked), but will file a new review if they request one.

Summary The ElementTiming API will allow developers to know when certain important text elements are first displayed on the screen. It will also enable analytics providers to measure the display time of text that takes up a large fraction of the viewport when they first show up. Motivation Developers should be informed of the time at which key elements of their website are first rendered. Usually this means images and/or text. Text is important for news websites, articles of online encyclopedias, email providers, etc. First Contentful Paint is insufficient because it is triggered with almost any element. Risks

Interoperability and Compatibility There is risk that this feature is not implemented by other browser vendors but we have already started conversations and gotten feedback on the WebPerf WG. Firefox: No public signals Edge: No public signals Safari: No public signals Web developers: No signals

Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)? Yes Is this feature fully tested by web-platform-tests? To be implemented Link to entry on the Chrome Platform Status https://www.chromestatus.com/features/6230814637424640