Scroll Anchoring is a new feature of Google Chrome 51 and newer that prevents visible jumps of the active page when offscreen content changes.

You may have experienced the following situation when using a browser like Google Chrome: you load a page and some text is loaded quickly. You begin to read the text and scroll a bit or a lot, and suddenly the page begins to scroll automatically as other elements, images or media, are added to the page.

You lose sight of the position you were at when that happens. This scroll jumping can be confusing, as you need to locate the position on the page when things started to jump around to continue reading.

These visible jumps, when you start to scroll while a page is loading, is problematic on the desktop, and maybe even more so on mobile devices.

Scroll Anchoring

Scroll Anchoring has been designed to prevent these visible jumps from happening in Chrome. Basically, what the feature does is adjust the page in the background without jumping away from the part that is visible on the screen.

The feature is not enabled by default but part of the browser’s experimental flags. These features are not yet ready for prime time, or need further testing, before Google makes a decision whether to integrate it natively in Chrome or remove it again.

To enable scroll anchoring in Google Chrome, do the following:

1. Make sure you are running at least Google Chrome 51. Easiest way to find out is to load chrome://version/ and check the version that is displayed.
2. If that is the case, load chrome://flags/#enable-scroll-anchoring to jump directly to the preference.
3. On mobile, you may find it easier to load chrome://flags and use the built-in search to find anchor to jump to it instead.
4. Switch it to enabled to turn it on.
5. Restart google Chrome to complete the change.

The feature is available for all desktop versions of Google Chrome, for Chrome OS and for Chrome on Android.

To turn it off again, repeat the process outlined above but switch the preference to disabled this time to do so.

Source: http://www.ghacks.net/