Step 4 in skip the page transition algorithm says that the DOM change callback has to be invoked synchronously. However, the skip the page transition algorithm sometimes runs as part of the update the rendering, and we really want to avoid running (new) script in those steps.

We should make it asynchronous. The question is should we just make it asynchronous for all places that run the skip the page transition algorithm, or should it be conditional?

I'm leaning towards just make it all asynchronous, but I'm unsure if there are cases where synchronous invocation is important.

/cc @khushalsagar @jakearchibald