Google has implemented a new feature into Chrome mobile called: “scroll anchoring”. Without getting too technical, the update will “lock content you’re currently looking at to the screen, keeping you in the same spot so you can keep reading,” all while the page continues to load.
“This feature works by locking the scroll position on an on-screen element to keep our users in the same spot even as offscreen content continues to load,” Google wrote in a blog, which uses a Recode story as example (oops). In the browser without Scroll Anchoring, the page jumps back to the top after it finishes loading, while the other stays where the user has scrolled to.
This is particularly helpful for mobile browsers, where more of the content gets pushed down when the page skips back up top.
It locks the page content to the screen, preventing the content from jumping all over the screen while everything is still being loaded. This feature has been available behind the #enable-scroll-anchoring flag for a while now, but it became default with the release of Chrome 56.
Google claims the feature is, on average, helping prevent three jumps per page view, and encourages developers to check out its Exclusion API if they need to disable anchors on pages where they may be unwanted.