[manigandham]

Yes. I'm in adtech. 60% of browsers are mobile/tablet which are already fixed. The rest are almost always fullscreen. Maybe 2% have non-standard sizes.

[meruru]

When you two say fullscreen, surely you mean maximized? I imagine a sizeable fraction of users don't even know how to fullscreen a window.

[manigandham]

yes

[missblit]

Fixed except when the user enables android split-screen mode! I believe split-screen mode implies the height of the browser window can change at runtime (in a JS visible way), but haven't looked at it recently.