The visual-viewport height (px) while the keyboard is open — i.e. the
space remaining above the keyboard — or null when it is closed. Use it
to clamp a position: fixed full-height container so its bottom edge
(chat input, control bar) stays above the keyboard.
The visual-viewport height (px) while the keyboard is open — i.e. the space remaining above the keyboard — or
nullwhen it is closed. Use it to clamp aposition: fixedfull-height container so its bottom edge (chat input, control bar) stays above the keyboard.