Created attachment 468822 [details] testcase In iOS Safari, if the browser UI is expanded, when focusing an input causing the appearance of the virtual keyboard, the visual viewport only gets resized at the end of the virtual keyboard opening/closing animation. When Safari's UI is collapsed (as a result of scrolling or when the user goes into settings and selects "Hide Toolbar"), or when it is absent (i.e. when the page has been installed with "Add to Home Screen", the visual viewport gets resized immediately after focusing the input, as expected. Steps to reproduce: - open the test case in Safari iOS - make sure the browser UI is expanded - tap the input - notice the visual viewport height displayed only gets updated at the end of the keyboard opening animation - tap "Done" in the virtual keyboard - notice the visual viewport height displayed only gets updated at the end of the keyboard closing animation It is expected that the visual viewport height gets updated and the resize event on visualViewport fires right away when the virtual keyboard starts opening/closing in all situations.
<rdar://problem/118999803>
Additional information: the delay is only present when Safari's address bar is positioned at the bottom, not when it is positioned at the top.