Browser behavior

Evidence has boundaries. Supported, tested, and fallback describe different things in this project.

Read the labels literally

Supported
The current runtime exposes a capability the package can detect.
Tested
A deterministic repository scenario covers the behavior.
Fallback
The package supplies documented geometry when an API is absent.

Keyboard inference is conservative

Without native Virtual Keyboard geometry, inference requires a focused editable element, no active zoom, and visual-bottom occlusion of at least 80 CSS pixels or 15% of layout height. Focus alone is never reported as an open keyboard.

Environment notes

iOS Safari

VisualViewport measurements are used when the API exists. Soft-keyboard inference remains conservative and needs physical-device verification.

Android Chrome

VisualViewport and Virtual Keyboard capabilities are detected independently. Capability detection is not a universal support claim.

Installed PWA

Display mode and browser chrome can change the available geometry. Test the installed experience on the devices you support.

Embedded WebViews

Host applications can expose different viewport behavior. Treat host-level testing as required evidence.