859330 - Request: Disable overscroll

Status: RESOLVED DUPLICATE of bug 705246

(Firefox for Android Graveyard :: Toolbar, defect)

Description

[Takahiro Endo]

User Agent: Mozilla/5.0 (Linux; Android 4.0.3; SC-02C Build/IML74K) AppleWebKit/537.31 (KHTML, like Gecko) Chrome/26.0.1410.58 Mobile Safari/537.31

Steps to reproduce:

This is my suggestion.

Firefox for Android uses kinetic bounce animation when we hit the edge of the content area. This bounce-back effect provides visually-rich and intuitive user experience. However, this feature is problematic on some websites like Twitter which assigns swipe down gesture to update the timeline. We can't pull it down as our wishes, and we have to move our finger for longer distance. (The autohide toolbar is also problematic, but I don't mention it here because it is off-topic.)

In addition, this effect is incompatible with some javascript APIs of the viewport or touch event. For example, event.screenX and screenY must return the absolute coordinates of the touch event from the top left of the device screen, but the screenXY returns the coordinates from the top left of the content area while the bounce animation. Consequently, we can't determine the absolute coordinates of a user's finger within the device screen, which makes developers inconvenient.

Therefore the bounce-back effect has many problems and few practical advantages. I think that the feature is not needed because it impairs intrinsic web experiences. So I would suggest to stop the feature.