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PageSwapEvent

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

The PageSwapEvent event object is made available inside handler functions for the pageswap event.

The pageswap event is fired when you navigate across documents, when the previous document is about to unload. During a cross-document navigation, the PageSwapEvent event object allows you to manipulate the related view transition (providing access to the relevant ViewTransition object) from the document being navigated from, if a view transition was triggered by the navigation. It also provides access to information on the navigation type and current and destination documents.

Constructor

PageSwapEvent(): Creates a new PageSwapEvent object instance.

Instance properties

activation Read only: Contains a NavigationActivation object containing the navigation type and current and destination document history entries for a same-origin navigation. If the navigation has a cross-origin URL anywhere in the redirect chain, it returns null.
viewTransition Read only: Contains a ViewTransition object representing the active view transition for the cross-document navigation.

Examples

window.addEventListener("pageswap", async (e) => {
  // Only run this if an active view transition exists
  if (e.viewTransition) {
    const currentUrl = e.activation.from?.url
      ? new URL(e.activation.from.url)
      : null;
    const targetUrl = new URL(e.activation.entry.url);

    // Going from profile page to homepage
    // ~> The big img and title are the ones!
    if (isProfilePage(currentUrl) && isHomePage(targetUrl)) {
      // Set view-transition-name values on the elements to animate
      document.querySelector(`#detail main h1`).style.viewTransitionName =
        "name";
      document.querySelector(`#detail main img`).style.viewTransitionName =
        "avatar";

      // Remove view-transition-names after snapshots have been taken
      // Stops naming conflicts resulting from the page state persisting in BFCache
      await e.viewTransition.finished;
      document.querySelector(`#detail main h1`).style.viewTransitionName =
        "none";
      document.querySelector(`#detail main img`).style.viewTransitionName =
        "none";
    }

    // Going to profile page
    // ~> The clicked items are the ones!
    if (isProfilePage(targetUrl)) {
      const profile = extractProfileNameFromUrl(targetUrl);

      // Set view-transition-name values on the elements to animate
      document.querySelector(`#${profile} span`).style.viewTransitionName =
        "name";
      document.querySelector(`#${profile} img`).style.viewTransitionName =
        "avatar";

      // Remove view-transition-names after snapshots have been taken
      // Stops naming conflicts resulting from the page state persisting in BFCache
      await e.viewTransition.finished;
      document.querySelector(`#${profile} span`).style.viewTransitionName =
        "none";
      document.querySelector(`#${profile} img`).style.viewTransitionName =
        "none";
    }
  }
});

Note: See List of Chrome DevRel team members for the live demo this code is taken from.

Specifications

Specification
HTML> # the-pageswapevent-interface>

Browser compatibility